ARM64: dts: meson-axg: describe pin DT info for I2C controller

Describe all the pin mux for the I2C controller which found in
Meson-AXG SoC.

Signed-off-by: Jian Hu <jian.hu@amlogic.com>
Signed-off-by: Yixun Lan <yixun.lan@amlogic.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>