sandbox: config: Enable sandbox command

The 'sb' command allows loading files from the host, and listing
directories.

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

include/configs/sandbox.h

@@ -97,6 +97,8 @@
 #define CONFIG_SHA1
 #define CONFIG_SHA256
 
+#define CONFIG_CMD_SANDBOX
+
 #define CONFIG_BOOTARGS ""
 
 #define CONFIG_EXTRA_ENV_SETTINGS	"stdin=serial\0" \