dt-bindings: pinctrl: Add bindings for new Ingenic SoCs.

Add the pinctrl bindings for the JZ4730 SoC, the JZ4750 SoC,
the JZ4755 SoC, the JZ4775 SoC and the X2000 SoC from Ingenic.

Signed-off-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/1618757073-1724-8-git-send-email-zhouyanjie@wanyeetech.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>