dquot: cleanup dquot drop routine

Get rid of the drop dquot operation - it is now always called from
the filesystem and if a filesystem really needs it's own (which none
currently does) it can just call into it's own routine directly.

Rename the now static low-level dquot_drop helper to __dquot_drop
and vfs_dq_drop to dquot_drop to have a consistent namespace.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/jfs/inode.c b/fs/jfs/inode.c
index 2562d18..22fa412 100644
--- a/fs/jfs/inode.c
+++ b/fs/jfs/inode.c
@@ -160,7 +160,7 @@
 		 */
 		vfs_dq_init(inode);
 		dquot_free_inode(inode);
-		vfs_dq_drop(inode);
+		dquot_drop(inode);
 	}
 
 	clear_inode(inode);