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>

fs/ufs/super.c

@@ -1434,7 +1434,7 @@ static void destroy_inodecache(void)
 
 static void ufs_clear_inode(struct inode *inode)
 {
-	vfs_dq_drop(inode);
+	dquot_drop(inode);
 }
 
 #ifdef CONFIG_QUOTA