mwifiex: fix association issue with AP configured in hidden SSID mode

mwifiex: fix association issue with AP configured in hidden SSID mode

Firmware expects 'max_ssid_length' field in
'struct mwifiex_ie_types_wildcard_ssid_params' to be '0' for
performing SSID specific scan. Currently driver updates it with
an actual SSID length. Hence UUT is not able to find the AP
configured in hidden SSID mode in scan results and association
fails.

max_ssid_length is filled with '0' to fix the issue.

Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>