bcm53xx: prepare for building Tenda AC9 TRX image

It'll be enabled when we complete basic support.

Signed-off-by: Rafał Miłecki <[email protected]>

target/linux/bcm53xx/image/Makefile

@@ -219,6 +219,14 @@ define Device/smartrg-sr400ac
   IMAGE/trx := append-rootfs | trx-serial
 endef
 
+define Device/tenda-ac9
+  DEVICE_TITLE := Tenda AC9
+  DEVICE_PACKAGES := $(USB2_PACKAGES)
+  IMAGES := trx
+  IMAGE/trx := append-rootfs | trx-serial
+endef
+# TARGET_DEVICES += tenda-ac9
+
 TARGET_DEVICES += \
 	netgear-r6250 netgear-r6300-v2 netgear-r8000 \
 	smartrg-sr400ac