iwlwifi: mvm: extend time event duration

Before authentication, we start a time event during
which we wait for a beacon in order to sync our timers.
If we didn't hear the beacon during this time - we abandon
the connection. However, in congested environment, it was
observed we might not hear beacons in that time slot.
Extend the time event to give the connection a better chance.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>