i40e: Add zero-initialization of AQ command structures

Zero-initialize AQ command data structures to comply with
API specifications.

Fixes: 2f4b411a ("i40e: Enable cloud filters via tc-flower")
Fixes: f4492db1 ("i40e: Add NPAR BW get and set functions")
Signed-off-by: Andrzej Sawuła <andrzej.sawula@intel.com>
Signed-off-by: Mateusz Palczewski <mateusz.palczewski@intel.com>
Reviewed-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>