ramips: fix default usb support for nexx wt3020-8M

the nexx wt3020-8M has a usb 2.0 port,
add usb 2.0 support packages to its default package list.

Signed-off-by: Alberto Bursi <[email protected]>

target/linux/ramips/image/mt7620.mk

@@ -485,6 +485,7 @@ define Device/wt3020-8M
   IMAGE/factory.bin := $$(sysupgrade_bin) | check-size $$$$(IMAGE_SIZE) | \
 	poray-header -B WT3020 -F 8M
   DEVICE_TITLE := Nexx WT3020 (8MB)
+  DEVICE_PACKAGES := kmod-usb2 kmod-usb-ohci
 endef
 TARGET_DEVICES += wt3020-8M