configs: sama5d2_xplained: enable ext4 command support

To support loading the zImage + DTB from the rootfs ext4 partitions,
enable the ext4 command support.

Based on original work by Wenyou Yang

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
diff --git a/configs/sama5d2_xplained_mmc_defconfig b/configs/sama5d2_xplained_mmc_defconfig
index 066fdb3..6d1dc92 100644
--- a/configs/sama5d2_xplained_mmc_defconfig
+++ b/configs/sama5d2_xplained_mmc_defconfig
@@ -34,6 +34,7 @@
 CONFIG_CMD_USB=y
 CONFIG_CMD_DHCP=y
 CONFIG_CMD_PING=y
+CONFIG_CMD_EXT4=y
 CONFIG_CMD_FAT=y
 CONFIG_OF_CONTROL=y
 CONFIG_SPL_OF_CONTROL=y
diff --git a/configs/sama5d2_xplained_spiflash_defconfig b/configs/sama5d2_xplained_spiflash_defconfig
index 87bca1f..f4333ea 100644
--- a/configs/sama5d2_xplained_spiflash_defconfig
+++ b/configs/sama5d2_xplained_spiflash_defconfig
@@ -32,6 +32,7 @@
 CONFIG_CMD_USB=y
 CONFIG_CMD_DHCP=y
 CONFIG_CMD_PING=y
+CONFIG_CMD_EXT4=y
 CONFIG_CMD_FAT=y
 CONFIG_OF_CONTROL=y
 CONFIG_SPL_OF_CONTROL=y