ASoC: fsl_spdif: Add support for i.MX8QM platform

On i.MX8QM, there are separate interrupts for TX and RX.

As the EDMA can't be configured to swing back to first FIFO
after writing the second FIFO, so we need to force the burst
size to be 2 on i.MX8QM. And EDMA don't support to shift
the data from S24_LE to S16_LE, so the supported TX format
is also different on i.MX8QM.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Link: https://lore.kernel.org/r/1602739728-4433-2-git-send-email-shengjiu.wang@nxp.com


Signed-off-by: Mark Brown <broonie@kernel.org>