mm, slub: ensure irqs are enabled for kmemcheck

mm, slub: ensure irqs are enabled for kmemcheck

kmemcheck_alloc_shadow() requires irqs to be enabled, so wait to disable
them until after its called for __GFP_WAIT allocations.

This fixes a warning for such allocations:

	WARNING: at kernel/lockdep.c:2739 lockdep_trace_alloc+0x14e/0x1c0()

Acked-by: Fengguang Wu <[email protected]>
Acked-by: Steven Rostedt <[email protected]>
Tested-by: Fengguang Wu <[email protected]>
Signed-off-by: David Rientjes <[email protected]>
Signed-off-by: Pekka Enberg <[email protected]>