arm64: dts: freescale: Add imx8mp-venice-gw72xx-2x

The Gateworks imx8mp-venice-gw72xx-2x consists of a SOM + baseboard.

The GW702x SOM contains the following:
 - i.MX8M Plus SoC
 - LPDDR4 memory
 - eMMC Boot device
 - Gateworks System Controller (GSC) with integrated EEPROM, button
   controller, and ADC's
 - PMIC
 - SOM connector providing:
  - eQoS GbE MII
  - 1x SPI
  - 2x I2C
  - 4x UART
  - 2x USB 3.0
  - 1x PCI
  - 1x SDIO (4-bit 3.3V)
  - 1x SDIO (4-bit 3.3V/1.8V)
  - GPIO

The GW72xx Baseboard contains the following:
 - GPS
 - microSD
 - off-board I/O connector with SPI
 - off-board I/O connector with I2C, and GPIO
 - off-board I/O connector with MIPI DSI, MIPI CSI, I2C, and GPIO
 - off-board I/O connector with RS232 and RS485
 - EERPOM
 - USB 3.0 HUB
 - USB 3.0 TypeA socket
 - USB 2.0 Micro-B OTG socket
 - Accelerometer
 - 1x GbE (eQoS)
 - 1x GbE (PCI)
 - PCIe clock generator
 - PCIe switch
 - 1x full-length miniPCIe socket with PCI and USB2.0
 - 1x full-length miniPCIe socket with PCI/USB3 (via mux) SIM, and USB2.0
 - 1x half-length miniPCIe socket with USB2.0 and USB3.0
 - USB Type-C with USB PD Sink capability and peripheral support
 - USB Type-C with USB 3.0 host support
 - Wide range DC input supply

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>