PS3: gelic: ignore scan info from zero SSID beacons

Some implementations of the hidden SSID APs emit beacons which have the zero
length SSID information element instead of SSID padded by null (\0) characters.
If the firmware of the PS3 wireless hardware meets these beacons, it abandons parsing
IEs. Thus guest OSes get the invalid scan information for the AP.

To work around this, ignore these scan informations from the list.

Signed-off-by: Masakazu Mokuno <mokuno@sm.sony.co.jp>
Signed-off-by: John W. Linville <linville@tuxdriver.com>