spi: dt-bindings: apple,spi: Add binding for Apple SPI controllers

spi: dt-bindings: apple,spi: Add binding for Apple SPI controllers

The Apple SPI controller is present in SoCs such as the M1 (t8103) and
M1 Pro/Max (t600x). This controller uses one IRQ and one clock, and
doesn't need any special properties, so the binding is trivial.

Signed-off-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Nick Chan <towinchenmi@gmail.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Janne Grunau <j@jannau.net>
Reviewed-by: Mark Kettenis <kettenis@openbsd.org>
Link: https://patch.msgid.link/20241106-asahi-spi-v5-1-e81a4f3a8e19@jannau.net
Signed-off-by: Mark Brown <broonie@kernel.org>