btrfs: drop unused parameter qgroup_reserved

Since commit 7775c8184ec0 ("btrfs: remove unused parameter from
btrfs_subvolume_release_metadata") parameter qgroup_reserved is not used
by caller of function btrfs_subvolume_reserve_metadata.  So remove it.

Signed-off-by: Gu JinXiang <gujx@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index c431ae0..7148aba 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4293,7 +4293,6 @@ int btrfs_delete_subvolume(struct inode *dir, struct dentry *dentry)
 	struct btrfs_trans_handle *trans;
 	struct btrfs_block_rsv block_rsv;
 	u64 root_flags;
-	u64 qgroup_reserved;
 	int ret;
 	int err;
 
@@ -4328,8 +4327,7 @@ int btrfs_delete_subvolume(struct inode *dir, struct dentry *dentry)
 	 * two for dir entries,
 	 * two for root ref/backref.
 	 */
-	err = btrfs_subvolume_reserve_metadata(root, &block_rsv,
-					       5, &qgroup_reserved, true);
+	err = btrfs_subvolume_reserve_metadata(root, &block_rsv, 5, true);
 	if (err)
 		goto out_up_write;