The error-path code can call rfkill_unregister() with a pointer which does
not contain the result of a call to rfkill_register().  It goes BUG().
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=12560.
Cc: Frans Pop <elendil@planet.nl>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Len Brown <lenb@kernel.org>
Acked-by: Matthew Garrett <mjg@redhat.com>
Reported-by: Helge Deller <deller@gmx.de>
Testted-by: Helge Deller <deller@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 
        return 0;
 register_wwan_err:
-       rfkill_unregister(bluetooth_rfkill);
+       if (bluetooth_rfkill)
+               rfkill_unregister(bluetooth_rfkill);
 register_bluetooth_error:
-       rfkill_unregister(wifi_rfkill);
+       if (wifi_rfkill)
+               rfkill_unregister(wifi_rfkill);
 add_sysfs_error:
        cleanup_sysfs(device);
        return err;