spi: dw-pci: Add support for Intel Elkhart Lake PSE SPI

Add support for Intel(R) Programmable Services Engine (Intel(R) PSE) SPI
controller in Intel Elkhart Lake when interface is assigned to the host
processor.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Link: https://lore.kernel.org/r/20190812101344.3975-1-jarkko.nikula@linux.intel.com


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