arm64: dts: allwinner: a64: move I2C pinctrl to dtsi

There is only one pinmuxing available for each I2C controller.

So, move pinctrl for i2c0, i2c1 from board dts files into SoC dtsi.

By moving these pinctrls the i2c1 node from Nanopi A64 just have a
status, which is disabled already so remove the entire node from it.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>