arm: sun8i: h3: split Allwinner H3 .dtsi

The new Allwinner H5 SoC is pin-compatible to the H3 SoC, but with the
Cortex-A7 cores replaced by Cortex-A53 cores and the MMC controller
updated. So we should really share almost the whole .dtsi.
In preparation for that move the peripheral parts of the existing
sun8i-h3.dtsi into a new sunxi-h3-h5.dtsi.
The actual sun8i-h3.dtsi then includes that and defines the H3 specific
parts on top of it.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
[Icenowy: also split out mmc and gic, as well as pio and ccu's
 compatible, and make drop of skeleton into a seperated patch]
Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>