ARM: dts: Add initial Pistachio i.mx6q board support.

ARM: dts: Add initial Pistachio i.mx6q board support.

Working items:

- 800MHz CPU
- 2GB of RAM (DDR3)
- 4GB of eMMC storage
- 1T1R WiFi 2.4 GHz
- Power management support
- 1x 10/100/1000 Mbps Ethernet WAN port
- 2x USB 2.0 Host
- PCIe
- HDMI/VGA/LVDS display
- 1x UART for RS232/422/485
- 2x UART for RS232
- 1x UART for serial console
- 1x CAN bus

Specification: http://nutsboard.org/pistachio

Signed-off-by: YuanCheng Cheng <onlywig@gmail.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>