xfs: fix the indent in xfs_trans_mod_dquot

The formatting is strange in xfs_trans_mod_dquot, so do a reindent.

Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>