dt-bindings: arm: rockchip: Add Firefly Core-PX30-JD4 on baseboard

Add binding for the Firefly Core-PX30-JD4 SoM when used in conjunction
with the MB-JD4-PX30 baseboard.

Signed-off-by: Christopher Obbard <chris.obbard@collabora.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Dragan Simic <dsimic@manjaro.org>
Link: https://lore.kernel.org/r/20240718-rockchip-px30-firefly-v3-1-3835cdd22eae@collabora.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>