dts: sun8i-h3: add I2C0-2 peripherals to H3 SOC

These peripherals can only be muxed to these pins, so they are
associated in the DTSI instead of the board files. This makes it very
easy to enable them using overlays or u-boot commands:

 => fdt set /soc/i2c@01c2ac00 status okay

Signed-off-by: Jorik Jonker <jorik@kippendief.biz>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>