Add a driver for the SPI controller integrated on Apple SoCs. This is necessary to support the keyboard on Apple Silicon laopts since their keyboard uses an Apple-specific HID over SPI protocol. Signed-off-by: Mark Kettenis <kettenis@openbsd.org> Reviewed-by: Simon Glass <sjg@chromium.org> Tested on: Macbook Air M1 Tested-by: Simon Glass <sjg@chromium.org>