ramips: create image for mt7628 evb board

The image for the EVB board got lost with the merge of the mt7628 and
mt7688 subtargets.

Signed-off-by: Mathias Kresin <[email protected]>

target/linux/ramips/image/mt76x8.mk

@@ -88,6 +88,7 @@ define Device/mt7628
   DEVICE_TITLE := MediaTek MT7628 EVB
   DEVICE_PACKAGES := kmod-usb2 kmod-usb-ohci kmod-usb-ledtrig-usbport
 endef
+TARGET_DEVICES += mt7628
 
 define Device/omega2
   DTS := OMEGA2