block: use interrupts disabled version of raise_softirq_irqoff()

We already have interrupts disabled at that point, so use the
__raise_softirq_irqoff() variant.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/blk-iopoll.c b/block/blk-iopoll.c
index b9b3265..ca56420 100644
--- a/block/blk-iopoll.c
+++ b/block/blk-iopoll.c
@@ -202,7 +202,7 @@
 		local_irq_disable();
 		list_splice_init(&per_cpu(blk_cpu_iopoll, cpu),
 				 &__get_cpu_var(blk_cpu_iopoll));
-		raise_softirq_irqoff(BLOCK_IOPOLL_SOFTIRQ);
+		__raise_softirq_irqoff(BLOCK_IOPOLL_SOFTIRQ);
 		local_irq_enable();
 	}