Staging: rtl8192e: Do not send NULL BSSID events when not associated

If we're not associated, we should not send wireless events to let userspace
know that we just left an ESSID, simply because we havent yet joined it.
If we keep on doing that, wpa_supplicant could receive such events while
actually trying to join an ESSID, and thus decide to stop trying. This leads
to a lot of connection failures as this driver seems to be sending GIWAP
events quite a lot.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>