ath6kl: use custom MAC address for newly created interfaces

Firmware and driver generate MAC addresses for the second and third interfaces.
In addition to the existing algorithm, flip bit 7 of 5th octet. Since both
firmware and driver individually generate the MAC addresses, introduce a new
firmware capability bit to keep them compatible.

Signed-off-by: Aarthi Thiruvengadam <athiruve@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
diff --git a/drivers/net/wireless/ath/ath6kl/cfg80211.c b/drivers/net/wireless/ath/ath6kl/cfg80211.c
index a5f3d6e..a624a0c 100644
--- a/drivers/net/wireless/ath/ath6kl/cfg80211.c
+++ b/drivers/net/wireless/ath/ath6kl/cfg80211.c
@@ -3523,9 +3523,13 @@
 	vif->htcap[IEEE80211_BAND_5GHZ].ht_enable = true;
 
 	memcpy(ndev->dev_addr, ar->mac_addr, ETH_ALEN);
-	if (fw_vif_idx != 0)
+	if (fw_vif_idx != 0) {
 		ndev->dev_addr[0] = (ndev->dev_addr[0] ^ (1 << fw_vif_idx)) |
 				     0x2;
+		if (test_bit(ATH6KL_FW_CAPABILITY_CUSTOM_MAC_ADDR,
+			     ar->fw_capabilities))
+			ndev->dev_addr[4] ^= 0x80;
+	}
 
 	init_netdev(ndev);