staging: wlan-ng: Fix clamping of returned SSID length

Commit 2e254212 broke listing of available network names, since it
clamped the length of the returned SSID to WLAN_BSSID_LEN (6) instead of
WLAN_SSID_MAXLEN (32).

https://bugzilla.kernel.org/show_bug.cgi?id=52501



Signed-off-by: Tormod Volden <debian.tormod@gmail.com>
Cc: stable <stable@vger.kernel.org> # 3.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>