ARM: dts: meson8b: mxq: improve support for the TRONFY MXQ S805

The TRONFY MXQ comes with either 1GB or 2GB RAM.

Both variants share (like most boards based on Amlogic reference
designs):
- 10/100 PHY (IC Plus IP101GR) with GPIOH_4 being the reset line and
  GPIOH_3 the interrupt line
- SD card slot with the card detection GPIO at CARD_6
- VCCK is generated by PWM_C with a period of 1148ns and XTAL as input
  clock
- USB OTG exposed on one of the USB-A connectors
- 4-port USB hub with 3 ports exposed to the outside

There seem the multiple board revision out there according to various
forum posts:
- storage: eMMC or NAND flash
- wifi: Ampak AP6210 or Realtek 8189

Add support for the following functionality:
- SoC temperature (hwmon)
- changing the CPU voltage
- Ethernet connectivity
- SD card
- USB

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: hexdump <hexdump0815@googlemail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>