block: make blk_softirq_init() static

Sparse asked whether these could be static.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/blk-softirq.c b/block/blk-softirq.c
index e660d26..ce0efc6 100644
--- a/block/blk-softirq.c
+++ b/block/blk-softirq.c
@@ -161,7 +161,7 @@
 }
 EXPORT_SYMBOL(blk_complete_request);
 
-__init int blk_softirq_init(void)
+static __init int blk_softirq_init(void)
 {
 	int i;