ar71xx: use correct wan mac address for the TP-Link Archer C7 v4

The correct MAC address for this device is lan_mac +1, there is no
need to set lan_mac so use base_mac variable instead lan_mac.

Based on this PR for ath79:
openwrt#1726

Signed-off-by: David Santamaría Rogado <howl.nsp@gmail.com>
[fix alphabetical ordering, reword subject]
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

target/linux/ar71xx/base-files/etc/board.d/02_network

@@ -589,6 +589,10 @@ ar71xx_setup_macs()
 	local wan_mac=""
 
 	case $board in
+	archer-c7-v4)
+		base_mac=$(mtd_get_mac_binary config 8)
+		wan_mac=$(macaddr_add "$base_mac" 1)
+		;;
 	dgl-5500-a1|\
 	dir-825-c1)
 		wan_mac=$(mtd_get_mac_ascii nvram "wan_mac")
@@ -600,6 +604,13 @@ ar71xx_setup_macs()
 		lan_mac=$(mtd_get_mac_binary caldata 0)
 		wan_mac=$(mtd_get_mac_binary caldata 6)
 		;;
+	dir-869-a1|\
+	mynet-n750)
+		wan_mac=$(mtd_get_mac_ascii devdata "wanmac")
+		;;
+	esr900)
+		wan_mac=$(mtd_get_mac_ascii u-boot-env "wanaddr")
+		;;
 	fritz300e)
 		lan_mac=$(fritz_tffs -n maca -i $(find_mtd_part "tffs (1)"))
 		;;
@@ -608,13 +619,6 @@ ar71xx_setup_macs()
 		lan_mac=$(mtd_get_mac_binary product-info 8)
 		wan_mac=$(macaddr_add "$lan_mac" 1)
 		;;
-	esr900)
-		wan_mac=$(mtd_get_mac_ascii u-boot-env "wanaddr")
-		;;
-	dir-869-a1|\
-	mynet-n750)
-		wan_mac=$(mtd_get_mac_ascii devdata "wanmac")
-		;;
 	wlr8100)
 		lan_mac=$(mtd_get_mac_ascii u-boot-env "ethaddr")
 		wan_mac=$(mtd_get_mac_ascii u-boot-env "wanaddr")