ASoC: fsl_sai: separate 'is_dsp_mode' for tx and rx

The transmitter and receiver of SAI can be used for different dsp modes,
then 'is_dsp_mode' needs to be separated.

Expand 'is_dsp_mode' to array 'is_dsp_mode[]' to support different
configuration of tx and rx.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Link: https://patch.msgid.link/20250328085744.1893434-4-shengjiu.wang@nxp.com


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