arm64: allwinner: h6: add I2C nodes

Add device-tree nodes for i2c0 to i2c2, and also add relevant pinctrl
nodes.

Suggested-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Bhushan Shah <bshah@kde.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>