ath9k: Allow platform override without EEPROM override

Add a new platform data flag "use_eeprom" that indicates that the eeprom
found on the card itself should be used instead of the one present in
the platform data.

This allows to override the MAC address of a PCI card while preserving
the eeprom data from the card itself.

The default behavior is preserved.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/init.c

@@ -508,7 +508,7 @@ static int ath9k_init_softc(u16 devid, struct ath_softc *sc,
 	sc->tx99_power = MAX_RATE_POWER + 1;
 	init_waitqueue_head(&sc->tx_wait);
 
-	if (!pdata) {
+	if (!pdata || pdata->use_eeprom) {
 		ah->ah_flags |= AH_USE_EEPROM;
 		sc->sc_ah->led_pin = -1;
 	} else {