xfs: open code updating i_mode in xfs_set_acl

Rather than going through the big and hairy xfs_setattr_nonsize function,
just open code a transactional i_mode and i_ctime update.  This allows
to mark xfs_setattr_nonsize and remove the flags argument to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Gao Xiang <hsiangkao@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>