arm64: dts: meson-s4: add pinctrl node

Add pinctrl node for mesonn-s4

Signed-off-by: Qianggui Song <qianggui.song@amlogic.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lore.kernel.org/r/20220310030410.718-1-qianggui.song@amlogic.com