Add the initial support for pico-imx7d board based on Wig Cheng's
source code.
Add support for eMMC, USB gadget, I2C, PMIC and Ethernet.
For more information about this board, please visit:
http://www.technexion.org/products/pico/pico-som/pico-imx7-emmc
Signed-off-by: Vanessa Maegima
Reviewed-by: Fabio Estevam