cfg80211: decouple regulatory variables from cfg80211_mutex

We change regulatory code to be protected by its own regulatory
mutex and alleviate cfg80211_mutex to only be used to protect
cfg80211_rdev_list, the registered device list.

By doing this we will be able to work on regulatory core components
without having to have hog up the cfg80211_mutex. An example here is
we no longer need to use the cfg80211_mutex during driver specific
wiphy_apply_custom_regulatory(). We also no longer need it for the
the country IE regulatory hint; by doing so we end up curing this
new lockdep warning:

=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.31-rc4-wl #12
-------------------------------------------------------
phy1/1709 is trying to acquire lock:
 (cfg80211_mutex){+.+.+.}, at: [<ffffffffa00af852>] regulatory_hint_11d+0x32/0x3f0 [cfg80211]

but task is already holding lock:
 (&ifmgd->mtx){+.+.+.}, at: [<ffffffffa0144228>] ieee80211_sta_work+0x108/0x10f0 [mac80211]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #3 (&ifmgd->mtx){+.+.+.}:
       [<ffffffff810857b6>] __lock_acquire+0xd76/0x12b0
       [<ffffffff81085dd3>] lock_acquire+0xe3/0x120
       [<ffffffff814eeae4>] mutex_lock_nested+0x44/0x350
       [<ffffffffa0141bb8>] ieee80211_mgd_auth+0x108/0x1f0 [mac80211]
       [<ffffffffa0148563>] ieee80211_auth+0x13/0x20 [mac80211]
       [<ffffffffa00bc3a1>] __cfg80211_mlme_auth+0x1b1/0x2a0 [cfg80211]
       [<ffffffffa00bc516>] cfg80211_mlme_auth+0x86/0xc0 [cfg80211]
       [<ffffffffa00b368d>] nl80211_authenticate+0x21d/0x230 [cfg80211]
       [<ffffffff81416ba6>] genl_rcv_msg+0x1b6/0x1f0
       [<ffffffff81415c39>] netlink_rcv_skb+0x89/0xb0
       [<ffffffff814169d9>] genl_rcv+0x29/0x40
       [<ffffffff8141591d>] netlink_unicast+0x29d/0x2b0
       [<ffffffff81416514>] netlink_sendmsg+0x214/0x300
       [<ffffffff813e4407>] sock_sendmsg+0x107/0x130
       [<ffffffff813e45b9>] sys_sendmsg+0x189/0x320
       [<ffffffff81011f82>] system_call_fastpath+0x16/0x1b
       [<ffffffffffffffff>] 0xffffffffffffffff

-> #2 (&wdev->mtx){+.+.+.}:
       [<ffffffff810857b6>] __lock_acquire+0xd76/0x12b0
       [<ffffffff81085dd3>] lock_acquire+0xe3/0x120
       [<ffffffff814eeae4>] mutex_lock_nested+0x44/0x350
       [<ffffffffa00ab304>] cfg80211_netdev_notifier_call+0x1a4/0x390 [cfg80211]
       [<ffffffff814f3dff>] notifier_call_chain+0x3f/0x80
       [<ffffffff81075a91>] raw_notifier_call_chain+0x11/0x20
       [<ffffffff813f665a>] dev_open+0x10a/0x120
       [<ffffffff813f59bd>] dev_change_flags+0x9d/0x1e0
       [<ffffffff8144eb6e>] devinet_ioctl+0x6fe/0x760
       [<ffffffff81450204>] inet_ioctl+0x94/0xc0
       [<ffffffff813e25fa>] sock_ioctl+0x6a/0x290
       [<ffffffff8111e911>] vfs_ioctl+0x31/0xa0
       [<ffffffff8111ea9a>] do_vfs_ioctl+0x8a/0x5c0
       [<ffffffff8111f069>] sys_ioctl+0x99/0xa0
       [<ffffffff81011f82>] system_call_fastpath+0x16/0x1b
       [<ffffffffffffffff>] 0xffffffffffffffff

-> #1 (&rdev->mtx){+.+.+.}:
       [<ffffffff810857b6>] __lock_acquire+0xd76/0x12b0
       [<ffffffff81085dd3>] lock_acquire+0xe3/0x120
       [<ffffffff814eeae4>] mutex_lock_nested+0x44/0x350
       [<ffffffffa00ac4d0>] cfg80211_get_dev_from_ifindex+0x60/0x90 [cfg80211]
       [<ffffffffa00b21ff>] get_rdev_dev_by_info_ifindex+0x6f/0xa0 [cfg80211]
       [<ffffffffa00b51eb>] nl80211_set_interface+0x3b/0x260 [cfg80211]
       [<ffffffff81416ba6>] genl_rcv_msg+0x1b6/0x1f0
       [<ffffffff81415c39>] netlink_rcv_skb+0x89/0xb0
       [<ffffffff814169d9>] genl_rcv+0x29/0x40
       [<ffffffff8141591d>] netlink_unicast+0x29d/0x2b0
       [<ffffffff81416514>] netlink_sendmsg+0x214/0x300
       [<ffffffff813e4407>] sock_sendmsg+0x107/0x130
       [<ffffffff813e45b9>] sys_sendmsg+0x189/0x320
       [<ffffffff81011f82>] system_call_fastpath+0x16/0x1b
       [<ffffffffffffffff>] 0xffffffffffffffff

other info that might help us debug this:

3 locks held by phy1/1709:
 #0:  ((wiphy_name(local->hw.wiphy))){+.+.+.}, at: [<ffffffff8106b45d>] worker_thread+0x19d/0x340
 #1:  (&ifmgd->work){+.+.+.}, at: [<ffffffff8106b45d>] worker_thread+0x19d/0x340
 #2:  (&ifmgd->mtx){+.+.+.}, at: [<ffffffffa0144228>] ieee80211_sta_work+0x108/0x10f0 [mac80211]

Reported-by: Reinette Chatre <reinette.chatre@intel.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>