b43: Fix oops on unload when firmware not found

commit f89ff644 upstream.

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 2d838bb6 fixed the same problem
for b43legacy.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Tested-by: Markus Kanet <dvmailing@gmx.eu>
Cc: Markus Kanet <dvmailing@gmx.eu>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/wireless/b43/main.c

@@ -5430,6 +5430,8 @@ 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) {
 		/* Restore the queues count before unregistering, because firmware detect
 		 * might have modified it. Restoring is important, so the networking