ARM: dts: meson8m2: add support for the Tronsmart MXIII Plus

The Tronsmart MXIII Plus is an Android TV box which uses the Amlogic
S812 (Meson8m2) SoC. It uses a Realtek RTL8211F RGMII Ethernet PHY as
well as a Ricoh RN5T618 system power controller. It also comes with an
Ampak AP6330 SDIO wifi/Bluetooth combo chip (support for wifi and
Bluetooth is currently not added because the Linux drivers currently
only support one MMC controller and that is used for the SD card).

Signed-off-by: Oleg Ivanov <balbes-150@yandex.ru>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>