const: make block_device_operations const

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index bbb7944..edda9ea 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1438,7 +1438,7 @@
 	return 0;
 }
 
-static struct block_device_operations lo_fops = {
+static const struct block_device_operations lo_fops = {
 	.owner =	THIS_MODULE,
 	.open =		lo_open,
 	.release =	lo_release,