dt-bindings: input: Goodix SPI HID Touchscreen

The Goodix GT7986U touch controller report touch data according to the
HID protocol through the SPI bus. However, it is incompatible with
Microsoft's HID-over-SPI protocol.

Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Charles Wang <charles.goodix@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>