btrfs: sink gfp_t parameter to btrfs_qgroup_trace_extent

All callers pass GFP_NOFS, we can drop the parameter and use it
directly.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h
index 3fb5459..7bffa10 100644
--- a/fs/btrfs/qgroup.h
+++ b/fs/btrfs/qgroup.h
@@ -321,7 +321,7 @@ int btrfs_qgroup_trace_extent_post(struct btrfs_trans_handle *trans,
  * (NULL trans)
  */
 int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans, u64 bytenr,
-			      u64 num_bytes, gfp_t gfp_flag);
+			      u64 num_bytes);
 
 /*
  * Inform qgroup to trace all leaf items of data