ath5k: add missing iounmap to AHB probe removal

When our driver device is removed on the AHB bus, our IO memory is never unmapped.
Signed-off-by: NJonathan Bither <jonbither@gmail.com>
Reviewed-by: NPavel Roskin <proski@gnu.org>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath5k/ahb.c

@@ -220,6 +220,7 @@ static int ath_ahb_remove(struct platform_device *pdev)
 	}
 
 	ath5k_deinit_ah(ah);
+	iounmap(ah->iobase);
 	platform_set_drvdata(pdev, NULL);
 	ieee80211_free_hw(hw);