spi: rockchip: Support SPI_CS_HIGH

1.Add standard spi-cs-high support
2.Refer to spi-controller.yaml for details

Signed-off-by: Jon Lin <jon.lin@rock-chips.com>
Link: https://lore.kernel.org/r/20210621104848.19539-2-jon.lin@rock-chips.com


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