ath5k: add a new bus op for reading the mac address

On AHB, the calibration data usually does not contain a valid MAC address,
the correct MAC address is stored in the board config.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath5k/base.c b/drivers/net/wireless/ath/ath5k/base.c
index c7da004..7583841 100644
--- a/drivers/net/wireless/ath/ath5k/base.c
+++ b/drivers/net/wireless/ath/ath5k/base.c
@@ -2880,7 +2880,7 @@
 	INIT_WORK(&sc->reset_work, ath5k_reset_work);
 	INIT_DELAYED_WORK(&sc->tx_complete_work, ath5k_tx_complete_poll_work);
 
-	ret = ath5k_eeprom_read_mac(ah, mac);
+	ret = ath5k_hw_common(ah)->bus_ops->eeprom_read_mac(ah, mac);
 	if (ret) {
 		ATH5K_ERR(sc, "unable to read address from EEPROM\n");
 		goto err_queues;