btrfs: qgroup: Drop fs_info parameter from btrfs_qgroup_trace_extent

It can be fetched from the transaction handle. In addition, remove the
WARN_ON(trans == NULL) because it's not possible to hit this condition.

Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 7b7498f..10f6a42 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -685,7 +685,7 @@ static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
 		 * as the owner of the file extent changed from log tree
 		 * (doesn't affect qgroup) to fs/file tree(affects qgroup)
 		 */
-		ret = btrfs_qgroup_trace_extent(trans, fs_info,
+		ret = btrfs_qgroup_trace_extent(trans,
 				btrfs_file_extent_disk_bytenr(eb, item),
 				btrfs_file_extent_disk_num_bytes(eb, item),
 				GFP_NOFS);