Increase max scan IEs to allow big probe-req frames

Report a correct max-length for the scan IEs we can support, according
to the now larger size of the probe-req template.
Signed-off-by: Ido Reis <idor@ti.com>
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>