ARM: dts: Gateworks GW5510 support (i.MX6)

ARM: dts: Gateworks GW5510 support (i.MX6)

Add support for the Gateworks GW5510 board featuring:
 * i.MX6 SoC
 * up to 512MB DDR3
 * up to 2GB NAND flash
 * 1x miniPCIe socket (with USB)
 * HDMI out (micro-HDMI)
 * HDMI in (micro-HDMI) (currently supported by only vendor kernel)
 * TTL level I/O (supported by GW16111 breakout board):
  * I2C
  * 2x UART
  * CAN
  * 2x DIO (GPIO/PWM)
  * USB OTG

For more details see:
 http://www.gateworks.com/product/item/ventana-gw5510-single-board-computer

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>