b43: Fix oops on unload when firmware not found

commit f89ff6441df06abc2d95f3ef67525923032d6283 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 2d838bb608e2d1f6cb4280e76748cb812dc822e7 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>

diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
index e4d6dc2..d6ffd43 100644
--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -5430,6 +5430,8 @@
 	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