amd8111e: fix dma_free_coherent context

Acoording commit aa24886e379d2b641c5117e178b15ce1d5d366ba,
dma_free_coherent() need irqs enabled.

This patch fix following warning messages:

WARNING: at linux/arch/x86/kernel/pci-dma.c:376 dma_free_coherent+0xaa/0xb0()

Call Trace:
 [<ffffffff8023f80f>] warn_on_slowpath+0x5f/0x90
 [<ffffffff80496ffa>] ? __kfree_skb+0x3a/0xa0
 [<ffffffff802a4723>] ? discard_slab+0x23/0x40
 [<ffffffff8021274a>] dma_free_coherent+0xaa/0xb0
 [<ffffffff8043668f>] amd8111e_close+0x10f/0x1b0
 [<ffffffff8049f3ae>] dev_close+0x5e/0xb0
 [<ffffffff8049efa1>] dev_change_flags+0xa1/0x1e0
 [<ffffffff806b2171>] ic_close_devs+0x36/0x4e
 [<ffffffff806b29ee>] ip_auto_config+0x581/0x10f3
 [<ffffffff803a6e19>] ? kobject_add+0x69/0x90
 [<ffffffff803a698a>] ? kobject_get+0x1a/0x30
 [<ffffffff803a785b>] ? kobject_uevent+0xb/0x10
 [<ffffffff803a6c62>] ? kset_register+0x52/0x60
 [<ffffffff803a6f9b>] ? kset_create_and_add+0x6b/0xa0
 [<ffffffff804e2e74>] ? tcp_ca_find+0x24/0x50
 [<ffffffff806b246d>] ? ip_auto_config+0x0/0x10f3
 [<ffffffff8020903c>] _stext+0x3c/0x150
 [<ffffffff802772d3>] ? register_irq_proc+0xd3/0xf0
 [<ffffffff802f0000>] ? mb_cache_create+0x80/0x1f0
 [<ffffffff80688693>] kernel_init+0x141/0x1b8
 [<ffffffff80688552>] ? kernel_init+0x0/0x1b8
 [<ffffffff8020d609>] child_rip+0xa/0x11
 [<ffffffff80688552>] ? kernel_init+0x0/0x1b8
 [<ffffffff80688552>] ? kernel_init+0x0/0x1b8
 [<ffffffff8020d5ff>] ? child_rip+0x0/0x11

Signed-off-by: Chunbo Luo <chunbo.luo@windriver.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>