ramips: fix Omnima MiniEMBWiFi image

Reference the Omnima MiniEMBWiFi device tree source file in the image
build code. Otherwise the dts of the image processed before is used.

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

target/linux/ramips/image/rt305x.mk

@@ -462,6 +462,7 @@ endef
 TARGET_DEVICES += miniembplug
 
 define Device/miniembwifi
+  DTS := MINIEMBWIFI
   DEVICE_TITLE := Omnima MiniEMBWiFi
 endef
 TARGET_DEVICES += miniembwifi