This adds support for the Zodiac Inflight Innovations RDU2 board,
which has both a Quad and a QuadPlus variant.

The board supports different panels, with the bootloader patching
in the correct compatible, depending on the hardware configuration.
Signed-off-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Tested-by: NNikita Yushchenko <nikita.yoush@cogentembedded.com>
Tested-by: NChris Healy <cphealy@gmail.com>
Signed-off-by: NShawn Guo <shawnguo@kernel.org>