dt-bindings: mfd: syscon: Add nuvoton,ma35d1-sys compatible

Add Nuvoton ma35d1 system registers compatible.

Signed-off-by: Jacky Huang <ychuang3@nuvoton.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230328021912.177301-6-ychuang570808@gmail.com