pinctrl: Ingenic: Add SSI pins support for JZ4770 and JZ4780.

Add SSI pins support for the JZ4770 SoC and the
JZ4780 SoC from Ingenic.
Signed-off-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20200913065836.12156-2-zhouyanjie@wanyeetech.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>