Initial support for Utilite Pro

1. Add new board 'utilite_pro'
2. Use Nitrogen6x 2GB RAM config (DCD) for now.
2. Assume SDHC3 is always present because has it no CD pin wired.
3. Read NOR Flash for uboot environment (turn off with CONFIG_ENV_IS_IN_SPI_FLASH)
4. Support imx ethernet phy.
5. Add USB support (turn on with CONFIG_CMD_USB)
6. Add simple HDMI support (turn on with #define CONFIG_VIDEO)