pinctrl: Add support for ADI SC5XX-family pinctrl

pinctrl: Add support for ADI SC5XX-family pinctrl

This adds support for pin configuration on the Analog Devices SC5XX SoC
family. This commit is largely a port of the Linux driver, which has not
yet been submitted upstream.

Co-developed-by: Nathan Barrett-Morrison <nathan.morrison@timesys.com>
Signed-off-by: Nathan Barrett-Morrison <nathan.morrison@timesys.com>
Co-developed-by: Ian Roberts <ian.roberts@timesys.com>
Signed-off-by: Ian Roberts <ian.roberts@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: Greg Malysa <malysagreg@gmail.com>