lantiq: drop unused variable from image build code

Remove the DEVICE_PROFILE variable. The variable isn't
used at all.

Signed-off-by: Mathias Kresin <dev@kresin.me>

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

@@ -13,7 +13,6 @@ endef
 
 define Device/TDW8970
   $(Device/lantiqTpLink)
-  DEVICE_PROFILE := TDW8970
   TPLINK_FLASHLAYOUT := 8Mltq
   TPLINK_HWID := 0x89700001
   TPLINK_HWREV := 1
@@ -26,7 +25,6 @@ TARGET_DEVICES += TDW8970
 
 define Device/TDW8980
   $(Device/lantiqTpLink)
-  DEVICE_PROFILE := TDW8980
   TPLINK_FLASHLAYOUT := 8Mltq
   TPLINK_HWID := 0x89800001
   TPLINK_HWREV := 14
@@ -39,7 +37,6 @@ TARGET_DEVICES += TDW8980
 
 define Device/VR200v
   $(Device/lantiqTpLink)
-  DEVICE_PROFILE := VR200v
   TPLINK_BOARD_ID := ArcherVR200V
   TPLINK_FLASHLAYOUT := 16Mltq
   TPLINK_HWID := 0x73b70801