configs/freescale_imx8mnevk: new defconfig

configs/freescale_imx8mnevk: new defconfig

This patch adds support for the i.MX8M Nano EVK Board [1].

The final boot image is created from uboot and firmware binaries in post
image script board/freescale/common/imx/imx8-bootloader-prepare.sh

Note that this config is based on 4.19.35_1.1.0 ; hence, the kernel
configuration needs host-openssl to build.

[1] https://www.nxp.com/design/development-boards/i-mx-evaluation-and-development-boards/evaluation-kit-for-the-i-mx-8m-nano-applications-processor:8MNANOD4-EVK

Signed-off-by: Stephane Viau <stephane.viau@oss.nxp.com>
Reviewed-by: Maeva Manuel <maeva.manuel@oss.nxp.com>
Reviewed-by: Julien Olivain <julien.olivain@oss.nxp.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>