dt-bindings: pinctrl: meson: Add compatible for S4

Add new compatible for Amlogic's Meson-S4 pin controller

Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Qianggui Song <qianggui.song@amlogic.com>
Link: https://lore.kernel.org/r/20220113031044.2665-2-qianggui.song@amlogic.com


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