make register_disk() static

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/block/genhd.c b/block/genhd.c
index 02e9fca..bf443a7 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -507,7 +507,7 @@
 	return 0;
 }
 
-void register_disk(struct gendisk *disk)
+static void register_disk(struct gendisk *disk)
 {
 	struct device *ddev = disk_to_dev(disk);
 	struct block_device *bdev;