arm64: dts: sun50i-a64-pinephone: Add touchscreen support

Pinephone has a Goodix GT917S capacitive touchscreen controller on
I2C0 bus. Add support for it.

Signed-off-by: Ondrej Jirman <megous@megous.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20200702081432.1727696-3-megous@megous.com


[Maxime: Removed the redundant pinctrl nodes]
Signed-off-by: Maxime Ripard <maxime@cerno.tech>