This adds a defconfig for sama5d2_xplained board to get environment from
eMMC. The defconfig is made from sama5d2_xplained_mmc_defconfig, with
'bootcmd' and 'bootargs' changed to kernel, device-tree and rootfs from
eMMC. The environment is expected to be found in eMMC's FAT
partition.
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
