spi: spidev: add compatible for arduino spi mcu interface

spi: spidev: add compatible for arduino spi mcu interface

Add compatible entry in spidev describing in Arduino UnoQ single-board
computer the interface between Qualcomm QRB2210 microprocessor and
STMicroelectronics STM32U585 microcontroller.
It is handled in user space by the arduino-router service.

Signed-off-by: Riccardo Mereu <r.mereu@arduino.cc>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://patch.msgid.link/20251120155825.121483-4-r.mereu.kernel@arduino.cc
Signed-off-by: Mark Brown <broonie@kernel.org>