arm: imx: Add support for GE Bx50v3 boards

Add support for GE B450v3, B650v3 and B850v3 boards. The boards
are based on Advantech BA16 module which has a i.MX6D processor.
The boards support:
 - FEC Ethernet
 - USB Ports
 - SDHC and MMC boot
 - SPI NOR
 - LVDS and HDMI display

Basic information about the module:
 - Module manufacturer: Advantech
 - CPU: Freescale ARM Cortex-A9 i.MX6D
 - SPECS:
     Up to 2GB Onboard DDR3 Memory;
     Up to 16GB Onboard eMMC NAND Flash
     Supports OpenGL ES 2.0 and OpenVG 1.1
     HDMI, 24-bit LVDS
     1x UART, 2x I2C, 8x GPIO,
     4x Host USB 2.0 port, 1x USB OTG port,
     1x micro SD (SDHC),1x SDIO, 1x SATA II,
     1x 10/100/1000 Mbps Ethernet, 1x PCIe X1 Gen2

Signed-off-by: Akshay Bhat <akshay.bhat@timesys.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>