board: sama5d2_xplained: Add default configuration for eMMC

Add the default configuration file for eMMC booting.

Signed-off-by: Wenyou Yang <wenyou.yang@microchip.com>

board/sama5d2_xplained/sama5d2_xplainedemmc_uboot_defconfig

@@ -0,0 +1,9 @@
+CONFIG_SAMA5D2_XPLAINED=y
+CONFIG_RAM_512MB=y
+CONFIG_DDR3=y
+CONFIG_SDCARD=y
+CONFIG_DEBUG=y
+# CONFIG_ENTER_NWD is not set
+CONFIG_ACT8865_SET_VOLTAGE=y
+# CONFIG_DISABLE_ACT8865_I2C is not set
+CONFIG_SUSPEND_ACT8945A_CHARGER=y