mx6sabre: Select CMD_EXT4 options

Add EXT4 support.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Acked-by: NOtavio Salvador <otavio@ossystems.com.br>

include/configs/mx6sabre_common.h

@@ -53,6 +53,8 @@
 #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