Add support for i.MX8QXP AI_ML board from Einfochips. This board is one
of the Consumer Edition boards of the 96Boards family based on i.MX8QXP
SoC from NXP/Freescale.

The initial support includes following peripherals which are tested and
known to be working:

1. Debug serial via UART2
2. uSD
3. WiFi
4. Ethernet

More information about this board can be found in Arrow website:
https://www.arrow.com/en/products/imx8-ai-ml/arrow-development-toolsSigned-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>