dt-bindings: display: st7701: Add Anbernic RG-ARC panel

dt-bindings: display: st7701: Add Anbernic RG-ARC panel

The RG-ARC panel is a panel specific to the Anbernic RG-ARC. It is 4
inches in size (diagonally) with a resolution of 480x640.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20231208154847.130615-3-macroalpha82@gmail.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231208154847.130615-3-macroalpha82@gmail.com