configs: sama5d2_ptc_ek: read environment from FAT
On our demo setup for SD card boot, the u-boot environment
is in a FAT partition.
This patch changes the default configuration, specifing that
the u-boot environment is in a FAT partition instead of raw MMC.
Signed-off-by: Andrei Stefanescu <andrei.stefanescu@microchip.com>
Acked-by: Eugen Hristev <eugen.hristev@microchip.com>