iwlwifi: mvm: quota command max_duration should be zero

For now, the firmware doesn't really use the field, but
it should be set to zero if there's no specific request.
Setting it to the max quota doesn't make sense.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>