xfs: remove the XFS_QM_IS[UGP]DQ macros

Remove these macros and use xfs_dquot_type() for everything.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>