spi: microchip-core-qspi: Add regular transfers

The driver for CoreQSPI only supports memory operations at present, so
add support for regular transfers so that the SD card slot and ADC on
the BeagleV Fire can be used.

Signed-off-by: Cyril Jean <cyril.jean@microchip.com>
Co-developed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20250620-splice-shelter-310771564886@spud


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