ar71xx: image: simplify Embedded Wireless definitions

Signed-off-by: Piotr Dymacz <pepe2k@gmail.com>

target/linux/ar71xx/image/generic.mk

@@ -358,22 +358,17 @@ endef
 TARGET_DEVICES += ew-balin
 
 define Device/ew-dorin
+  $(Device/ew-balin)
   DEVICE_TITLE := Embedded Wireless Dorin Platform
-  DEVICE_PACKAGES := kmod-usb-core kmod-usb-chipidea
   BOARDNAME := EW-DORIN
   CONSOLE := ttyATH0,115200
-  IMAGE_SIZE := 16000k
-  MTDPARTS := spi0.0:256k(u-boot)ro,64k(u-boot-env),16000k(firmware),64k(art)ro
 endef
 TARGET_DEVICES += ew-dorin
 
 define Device/ew-dorin-router
+  $(Device/ew-dorin)
   DEVICE_TITLE := Embedded Wireless Dorin Router Platform
-  DEVICE_PACKAGES := kmod-usb-core kmod-usb-chipidea
   BOARDNAME := EW-DORIN-ROUTER
-  CONSOLE := ttyATH0,115200
-  IMAGE_SIZE := 16000k
-  MTDPARTS := spi0.0:256k(u-boot)ro,64k(u-boot-env),16000k(firmware),64k(art)ro
 endef
 TARGET_DEVICES += ew-dorin-router