Enables support for ext4, the "load" command, and using bootz with raw initrds.

Index: u-boot/include/configs/mx53loco.h
===================================================================
--- u-boot.orig/include/configs/mx53loco.h
+++ u-boot/include/configs/mx53loco.h
@@ -46,6 +46,7 @@
 #define CONFIG_CMD_FS_GENERIC
 #define CONFIG_CMD_FAT
 #define CONFIG_CMD_EXT2
+#define CONFIG_CMD_EXT4
 #define CONFIG_DOS_PARTITION
 
 /* Eth Configs */
