spi: microchip: pci1xxxx: Add suspend and resume support for PCI1XXXX SPI driver

Implement suspend, resume callbacks, store config at suspend and restore
config at time of resume

Signed-off-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Link: https://lore.kernel.org/r/20221006050514.115564-3-tharunkumar.pasumarthi@microchip.com


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