imx6cuboxi: enable usb mass-storage gadget command

Enable the cli-command "ums" for usb mass-storage gadget support,
which is commonly useful for eMMC deployment.

Signed-off-by: Josua Mayer <[email protected]>

Author: Josua-SR

configs/mx6cuboxi_defconfig

@@ -27,6 +27,7 @@ CONFIG_CMD_GPIO=y
 CONFIG_CMD_MMC=y
 CONFIG_CMD_SATA=y
 CONFIG_CMD_USB=y
+CONFIG_CMD_USB_MASS_STORAGE=y
 CONFIG_CMD_CACHE=y
 CONFIG_CMD_EXT4_WRITE=y
 # CONFIG_SPL_ISO_PARTITION is not set