spi: amlogic-spifc-a1: add support for max_speed_hz

This patch sets the clock rate (spi_transfer->max_speed_hz) from the
amlogic_spifc_a1_exec_op().

Signed-off-by: Martin Kurbanov <mmkurbanov@sberdevices.ru>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20230706110331.19794-3-mmkurbanov@sberdevices.ru


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