sandbox: Enable ext4 and fat filesystems

These are useful for build-testing code, at least.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@ti.com>

include/configs/sandbox.h

@@ -32,6 +32,13 @@
 #define CONFIG_OF_LIBFDT
 #define CONFIG_LMB
 
+#define CONFIG_FS_FAT
+#define CONFIG_FS_EXT4
+#define CONFIG_EXT4_WRITE
+#define CONFIG_CMD_FAT
+#define CONFIG_CMD_EXT4
+#define CONFIG_CMD_EXT4_WRITE
+
 #define CONFIG_SYS_VSNPRINTF
 
 #define CONFIG_CMD_GPIO