[PATCH] fix deadlock in drivers/pci/msi.c

The lock validator caught another one: drivers/pci/msi.c is accessing
&irq_desc[i].lock with interrupts enabled (!).

The fix is to disable interrupts properly.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>