spi: xcomm: add gpiochip support

The hardware can expose one pin as a GPO. Hence, register a simple
gpiochip to support it.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Co-developed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://patch.msgid.link/20240705-dev-spi-xcomm-gpiochip-v2-1-b10842fc9636@analog.com


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