Bluetooth: Fix not closing SCO sockets in the BT_CONNECT2 state

With deferred setup for SCO, it is possible that userspace closes the
socket when it is in the BT_CONNECT2 state, after the Connect Request is
received but before the Accept Synchonous Connection is sent.

If this happens the following crash was observed, when the connection is
terminated:

[  +0.000003] hci_sync_conn_complete_evt: hci0 status 0x10
[  +0.000005] sco_connect_cfm: hcon ffff88003d1bd800 bdaddr 40:98:4e:32:d7:39 status 16
[  +0.000003] sco_conn_del: hcon ffff88003d1bd800 conn ffff88003cc8e300, err 110
[  +0.000015] BUG: unable to handle kernel NULL pointer dereference at 0000000000000199
[  +0.000906] IP: [<ffffffff810620dd>] __lock_acquire+0xed/0xe82
[  +0.000000] PGD 3d21f067 PUD 3d291067 PMD 0
[  +0.000000] Oops: 0002 [#1] SMP
[  +0.000000] Modules linked in: rfcomm bnep btusb bluetooth
[  +0.000000] CPU 0
[  +0.000000] Pid: 1481, comm: kworker/u:2H Not tainted 3.9.0-rc1-25019-gad82cdd #1 Bochs Bochs
[  +0.000000] RIP: 0010:[<ffffffff810620dd>]  [<ffffffff810620dd>] __lock_acquire+0xed/0xe82
[  +0.000000] RSP: 0018:ffff88003c3c19d8  EFLAGS: 00010002
[  +0.000000] RAX: 0000000000000001 RBX: 0000000000000246 RCX: 0000000000000000
[  +0.000000] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88003d1be868
[  +0.000000] RBP: ffff88003c3c1a98 R08: 0000000000000002 R09: 0000000000000000
[  +0.000000] R10: ffff88003d1be868 R11: ffff88003e20b000 R12: 0000000000000002
[  +0.000000] R13: ffff88003aaa8000 R14: 000000000000006e R15: ffff88003d1be850
[  +0.000000] FS:  0000000000000000(0000) GS:ffff88003e200000(0000) knlGS:0000000000000000
[  +0.000000] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[  +0.000000] CR2: 0000000000000199 CR3: 000000003c1cb000 CR4: 00000000000006b0
[  +0.000000] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  +0.000000] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[  +0.000000] Process kworker/u:2H (pid: 1481, threadinfo ffff88003c3c0000, task ffff88003aaa8000)
[  +0.000000] Stack:
[  +0.000000]  ffffffff81b16342 0000000000000000 0000000000000000 ffff88003d1be868
[  +0.000000]  ffffffff00000000 00018c0c7863e367 000000003c3c1a28 ffffffff8101efbd
[  +0.000000]  0000000000000000 ffff88003e3d2400 ffff88003c3c1a38 ffffffff81007c7a
[  +0.000000] Call Trace:
[  +0.000000]  [<ffffffff8101efbd>] ? kvm_clock_read+0x34/0x3b
[  +0.000000]  [<ffffffff81007c7a>] ? paravirt_sched_clock+0x9/0xd
[  +0.000000]  [<ffffffff81007fd4>] ? sched_clock+0x9/0xb
[  +0.000000]  [<ffffffff8104fd7a>] ? sched_clock_local+0x12/0x75
[  +0.000000]  [<ffffffff810632d1>] lock_acquire+0x93/0xb1
[  +0.000000]  [<ffffffffa0022339>] ? spin_lock+0x9/0xb [bluetooth]
[  +0.000000]  [<ffffffff8105f3d8>] ? lock_release_holdtime.part.22+0x4e/0x55
[  +0.000000]  [<ffffffff814f6038>] _raw_spin_lock+0x40/0x74
[  +0.000000]  [<ffffffffa0022339>] ? spin_lock+0x9/0xb [bluetooth]
[  +0.000000]  [<ffffffff814f6936>] ? _raw_spin_unlock+0x23/0x36
[  +0.000000]  [<ffffffffa0022339>] spin_lock+0x9/0xb [bluetooth]
[  +0.000000]  [<ffffffffa00230cc>] sco_conn_del+0x76/0xbb [bluetooth]
[  +0.000000]  [<ffffffffa002391d>] sco_connect_cfm+0x2da/0x2e9 [bluetooth]
[  +0.000000]  [<ffffffffa000862a>] hci_proto_connect_cfm+0x38/0x65 [bluetooth]
[  +0.000000]  [<ffffffffa0008d30>] hci_sync_conn_complete_evt.isra.79+0x11a/0x13e [bluetooth]
[  +0.000000]  [<ffffffffa000cd96>] hci_event_packet+0x153b/0x239d [bluetooth]
[  +0.000000]  [<ffffffff814f68ff>] ? _raw_spin_unlock_irqrestore+0x48/0x5c
[  +0.000000]  [<ffffffffa00025f6>] hci_rx_work+0xf3/0x2e3 [bluetooth]
[  +0.000000]  [<ffffffff8103efed>] process_one_work+0x1dc/0x30b
[  +0.000000]  [<ffffffff8103ef83>] ? process_one_work+0x172/0x30b
[  +0.000000]  [<ffffffff8103e07f>] ? spin_lock_irq+0x9/0xb
[  +0.000000]  [<ffffffff8103fc8d>] worker_thread+0x123/0x1d2
[  +0.000000]  [<ffffffff8103fb6a>] ? manage_workers+0x240/0x240
[  +0.000000]  [<ffffffff81044211>] kthread+0x9d/0xa5
[  +0.000000]  [<ffffffff81044174>] ? __kthread_parkme+0x60/0x60
[  +0.000000]  [<ffffffff814f75bc>] ret_from_fork+0x7c/0xb0
[  +0.000000]  [<ffffffff81044174>] ? __kthread_parkme+0x60/0x60
[  +0.000000] Code: d7 44 89 8d 50 ff ff ff 4c 89 95 58 ff ff ff e8 44 fc ff ff 44 8b 8d 50 ff ff ff 48 85 c0 4c 8b 95 58 ff ff ff 0f 84 7a 04 00 00 <f0> ff 80 98 01 00 00 83 3d 25 41 a7 00 00 45 8b b5 e8 05 00 00
[  +0.000000] RIP  [<ffffffff810620dd>] __lock_acquire+0xed/0xe82
[  +0.000000]  RSP <ffff88003c3c19d8>
[  +0.000000] CR2: 0000000000000199
[  +0.000000] ---[ end trace e73cd3b52352dd34 ]---

Cc: stable@vger.kernel.org [3.8]
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Tested-by: Frederic Dalleau <frederic.dalleau@intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>