ar71xx: fix Archer C7 5GHz MAC-address

The TP-Link firmware uses (primary_mac-1) as MAC-address
for the 5GHz WiFi. This applies the same behaviour to LEDE.

Currently, the MAC-address is retrieved from eth1, which
does not exist on the Archer C7 v4. As a result from this,
every C7 v4 with LEDE carries the same MAC-Address on the 5GHz WiFi.

patches/lede/0048-ar71xx-fix-Archer-C7-5GHz-MAC-address.patch

@@ -0,0 +1,36 @@
+From: David Bauer <mail@david-bauer.net>
+Date: Tue, 19 Dec 2017 02:32:47 +0100
+Subject: ar71xx: fix Archer C7 5GHz MAC-address
+
+The TP-Link firmware uses (primary_mac-1) as MAC-address
+for the 5GHz WiFi. This applies the same behaviour to LEDE.
+
+Currently, the MAC-address is retrieved from eth1, which
+does not exist on the Archer C7 v4. As a result from this,
+every C7 v4 with LEDE carries the same MAC-Address on the 5GHz WiFi.
+
+Signed-off-by: David Bauer <mail@david-bauer.net>
+
+diff --git a/target/linux/ar71xx/base-files/etc/hotplug.d/firmware/11-ath10k-caldata b/target/linux/ar71xx/base-files/etc/hotplug.d/firmware/11-ath10k-caldata
+index 96b8f6b9a4bdd6a1609a819e72ade315bccfb3c0..607bbd2c0ec4b59ba569550e9e0e87b80c7ddddb 100644
+--- a/target/linux/ar71xx/base-files/etc/hotplug.d/firmware/11-ath10k-caldata
++++ b/target/linux/ar71xx/base-files/etc/hotplug.d/firmware/11-ath10k-caldata
+@@ -47,6 +47,10 @@ board=$(ar71xx_board_name)
+ case "$FIRMWARE" in
+ "ath10k/cal-pci-0000:00:00.0.bin")
+ 	case $board in
++	archer-c7-v4)
++		ath10kcal_extract "art" 20480 2116
++		ath10kcal_patch_mac $(macaddr_add $(cat /sys/class/net/eth0/address) -1)
++		;;
+ 	cf-e380ac-v1|\
+ 	cf-e380ac-v2|\
+ 	dlan-pro-1200-ac|\
+@@ -92,7 +96,6 @@ case "$FIRMWARE" in
+ 		ath10kcal_extract "art" 20480 2116
+ 		ath10kcal_patch_mac $(macaddr_add $(cat /sys/class/net/eth0/address) -2)
+ 		;;
+-	archer-c7-v4|\
+ 	archer-c25-v1|\
+ 	tl-wdr6500-v2)
+ 		ath10kcal_extract "art" 20480 2116