Allwinner H3/H5 SoCs have an I2C controller at PL GPIO bank.

Add support for it in the device tree.
Signed-off-by: Ondrej Jirman <megous@megous.com>
[Icenowy: Change to use r_ccu and change pinmux node name]
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>