Add compatible string for new added platforms which support spdif module.
They are i.MX8QXP, i.MX8MM, i.MX8MN, i.MX8MQ.
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Link: https://lore.kernel.org/r/1615884053-4264-1-git-send-email-shengjiu.wang@nxp.comSigned-off-by: Mark Brown <broonie@kernel.org>