lantiq: xrx200_legacy: add alternative names for TP-Link TD-W9980(B)

The TP-Link TD-W9980(B) shares the same hardware with the TP-Link TD-W8980.
The only difference is that the TD-W8980 does not support VDSL. This is a
software limitation and once the software is changed, both work equally
supporting VDSL. This commit adds alternative names for devices so they
can be easily found in the firmware selector.

Signed-off-by: Aleksander Jan Bajkowski <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/17583
Signed-off-by: Hauke Mehrtens <[email protected]>
(cherry picked from commit b2b4ce15322c75bda0cae6fb2160a74270185831)

target/linux/lantiq/image/tp-link_legacy.mk

@@ -36,6 +36,12 @@ define Device/tplink_tdw8980
   $(Device/lantiqTpLink)
   DEVICE_MODEL := TD-W8980
   DEVICE_VARIANT := v1
+  DEVICE_ALT0_VENDOR := TP-LINK
+  DEVICE_ALT0_MODEL := TD-W9980
+  DEVICE_ALT0_VARIANT := v1
+  DEVICE_ALT1_VENDOR := TP-LINK
+  DEVICE_ALT1_MODEL := TD-W9980B
+  DEVICE_ALT1_VARIANT := v1
   TPLINK_FLASHLAYOUT := 8Mltq
   TPLINK_HWID := 0x89800001
   TPLINK_HWREV := 14