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/ext3/super.c b/fs/ext3/super.c
index 2277b1a..0163d0d 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -529,7 +529,7 @@
 {
 	struct ext3_block_alloc_info *rsv = EXT3_I(inode)->i_block_alloc_info;
 
-	vfs_dq_drop(inode);
+	dquot_drop(inode);
 	ext3_discard_reservation(inode);
 	EXT3_I(inode)->i_block_alloc_info = NULL;
 	if (unlikely(rsv))
@@ -753,7 +753,6 @@
 
 static const struct dquot_operations ext3_quota_operations = {
 	.initialize	= dquot_initialize,
-	.drop		= dquot_drop,
 	.write_dquot	= ext3_write_dquot,
 	.acquire_dquot	= ext3_acquire_dquot,
 	.release_dquot	= ext3_release_dquot,