nitrogen6x: config: enable EXT4 filesystem

Support reading/writing ext4 partitions.

Signed-off-by: Kevin Mihelich <kevin@archlinuxarm.org>
Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
diff --git a/include/configs/nitrogen6x.h b/include/configs/nitrogen6x.h
index 17559d8..469591f 100644
--- a/include/configs/nitrogen6x.h
+++ b/include/configs/nitrogen6x.h
@@ -77,6 +77,8 @@
 #define CONFIG_GENERIC_MMC
 #define CONFIG_BOUNCE_BUFFER
 #define CONFIG_CMD_EXT2
+#define CONFIG_CMD_EXT4
+#define CONFIG_CMD_EXT4_WRITE
 #define CONFIG_CMD_FAT
 #define CONFIG_DOS_PARTITION