spi: microchip-core: add support for word sizes of 1 to 32 bits

The current implementation only supports a word size of 8 bits,
which limits the devices it can be used with. Add support for any
word size between 1 and 32 bits, as supported by the hardware.

Signed-off-by: Steve Wilkins <steve.wilkins@raymarine.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20240715-cogwheel-uniquely-0d4ef518b809@wendy


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