spi: Add support for ADI SC5XX-family processor SPI peripherals

spi: Add support for ADI SC5XX-family processor SPI peripherals

This adds support for the ADI-specific SPI driver present in the ADI
SC5xx line of SoCs. This IP block is distinct from the QSPI/OSPI block
that uses the Cadence driver. Both may be used at once with appropriate
pin muxing configuration.

Co-developed-by: Greg Malysa <malysagreg@gmail.com>
Signed-off-by: Greg Malysa <malysagreg@gmail.com>
Co-developed-by: Angelo Dureghello <angelo.dureghello@timesys.com>
Signed-off-by: Angelo Dureghello <angelo.dureghello@timesys.com>
Co-developed-by: Ian Roberts <ian.roberts@timesys.com>
Signed-off-by: Ian Roberts <ian.roberts@timesys.com>
Co-developed-by: Piotr Wojtaszczyk <piotr.wojtaszczyk@timesys.com>
Signed-off-by: Piotr Wojtaszczyk <piotr.wojtaszczyk@timesys.com>
Signed-off-by: Vasileios Bimpikas <vasileios.bimpikas@analog.com>
Signed-off-by: Utsav Agarwal <utsav.agarwal@analog.com>
Signed-off-by: Arturs Artamonovs <arturs.artamonovs@analog.com>
Signed-off-by: Oliver Gaskell <Oliver.Gaskell@analog.com>
Signed-off-by: Nathan Barrett-Morrison <nathan.morrison@timesys.com>