sun8i: h3: Support H3 variant of Orange Pi Zero Plus 2

Orangepi Zero Plus 2 is an open-source single-board computer, available
in two Allwinner SOC variants, H3 and H5. We add support for H3 variant
here, as the H5 is already supported.

H3 Orangepi Zero Plus 2 has:
- Quad-core Cortex-A7
- 512MB DDR3
- microSD slot and 8GB eMMC
- Debug TTL UART
- HDMI
- Wifi + BT
- OTG + power supply

Sync dts from linux v5.2 commit:
"ARM: dts: sunxi: h3/h5: Remove stale pinctrl-names entry"
(sha1: 75f9a058838be9880afd75c4cb14e1bf4fe34a0b)
Commit:
"ARM: dts: sun8i: h3: Refactor the pinctrl node names"
(sha1: a4dc791974e568a15f7f37131729b1a6912f4811)
has been avoided as it breaks U-Boot build.

Signed-off-by: Diego Rondini <diego.rondini@kynetics.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>