ARM: dts: imx6: Add support for phyBOARD-Mira i.MX 6 DualLight/Solo RDK

Add support for the PHYTEC phyBOARD-Mira Low-Cost Rapid Development Kit
with i.MX 6DualLight/Solo with NAND.

Following interfaces are supported:
- 100 MBit Ethernet
- USB Host
- RS232
- HDMI

Signed-off-by: Christian Hemp <c.hemp@phytec.de>
Signed-off-by: Stefan Christ <s.christ@phytec.de>
Signed-off-by: Stefan Riedmueller <s.riedmueller@phytec.de>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>