configs: colibri_imx7: use DM_MMC

Now that device tree is in place use DM_MMC for Colibri iMX7
devices.

Signed-off-by: Stefan Agner <stefan.agner@toradex.com>
Acked-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
diff --git a/configs/colibri_imx7_defconfig b/configs/colibri_imx7_defconfig
index b919a29..5cda5ab 100644
--- a/configs/colibri_imx7_defconfig
+++ b/configs/colibri_imx7_defconfig
@@ -50,6 +50,7 @@
 CONFIG_DFU_MMC=y
 CONFIG_DM_GPIO=y
 CONFIG_DM_I2C=y
+CONFIG_DM_MMC=y
 CONFIG_FSL_ESDHC=y
 CONFIG_MTD=y
 CONFIG_NAND=y
@@ -64,7 +65,6 @@
 CONFIG_PMIC_RN5T567=y
 CONFIG_USB=y
 CONFIG_USB_EHCI_HCD=y
-CONFIG_USB_STORAGE=y
 CONFIG_USB_GADGET=y
 CONFIG_USB_GADGET_MANUFACTURER="Toradex"
 CONFIG_USB_GADGET_VENDOR_NUM=0x1b67