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: NFengguang Wu <fengguang.wu@intel.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Tested-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NPekka Enberg <penberg@kernel.org>