b43: Fix oops on unload when firmware not found

When b43 fails to find firmware when loaded, a subsequent unload will
oops due to calling ieee80211_unregister_hw() when the corresponding
register call was never made.

Commit 2d838bb608e2d1f6cb4280e76748cb812dc822e7 fixed the same problem
for b43legacy.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Tested-by: Markus Kanet <dvmailing@gmx.eu>
Cc: Stable <stable@vger.kernel.org> [V3.3.0+ (the patch will need to be refactored)]
Cc: Markus Kanet <dvmailing@gmx.eu>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/b43/main.c

@@ -5404,6 +5404,8 @@ static void b43_bcma_remove(struct bcma_device *core)
 	cancel_work_sync(&wldev->restart_work);
 
 	B43_WARN_ON(!wl);
+	if (!wldev->fw.ucode.data)
+		return;			/* NULL if firmware never loaded */
 	if (wl->current_dev == wldev && wl->hw_registred) {
 		b43_leds_stop(wldev);
 		ieee80211_unregister_hw(wl->hw);
@@ -5478,6 +5480,8 @@ static void b43_ssb_remove(struct ssb_device *sdev)
 	cancel_work_sync(&wldev->restart_work);
 
 	B43_WARN_ON(!wl);
+	if (!wldev->fw.ucode.data)
+		return;			/* NULL if firmware never loaded */
 	if (wl->current_dev == wldev && wl->hw_registred) {
 		b43_leds_stop(wldev);
 		ieee80211_unregister_hw(wl->hw);