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/include/linux/genhd.h b/include/linux/genhd.h
index 109d179..297df45 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -151,7 +151,7 @@
 	struct disk_part_tbl *part_tbl;
 	struct hd_struct part0;
 
-	struct block_device_operations *fops;
+	const struct block_device_operations *fops;
 	struct request_queue *queue;
 	void *private_data;