spi: spi-fsl-dspi: Enable modified transfer protocol on S32G

spi: spi-fsl-dspi: Enable modified transfer protocol on S32G

S32G supports modified transfer protocol where both host and target
devices sample later in the SCK period than in Classic SPI mode to allow
the logic to tolerate more delays in device pads and board traces. Set
MTFE bit in MCR register for frequencies higher than 25MHz.

Signed-off-by: Andra-Teodora Ilie <andra.ilie@nxp.com>
Signed-off-by: Bogdan-Gabriel Roman <bogdan-gabriel.roman@nxp.com>
Signed-off-by: Larisa Grigore <larisa.grigore@nxp.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Link: https://patch.msgid.link/20250522-james-nxp-spi-v2-11-bea884630cfb@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>