warp7: Switch to DM USB

This commit switches to DM USB for warp7 and warp7_bl33 defconfigs.

Signed-off-by: Pierre-Jean Texier <pjtexier@koncepto.io>
Signed-off-by: Joris Offouga <offougajoris@gmail.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
diff --git a/configs/warp7_defconfig b/configs/warp7_defconfig
index ae424ab..cabddad 100644
--- a/configs/warp7_defconfig
+++ b/configs/warp7_defconfig
@@ -51,6 +51,7 @@
 CONFIG_DM_SERIAL=y
 CONFIG_OPTEE=y
 CONFIG_USB=y
+CONFIG_DM_USB=y
 CONFIG_USB_EHCI_HCD=y
 CONFIG_MXC_USB_OTG_HACTIVE=y
 CONFIG_USB_GADGET=y