iwlwifi: mvm: support aggs of 64 frames in A000 family

A SCD bug was fixed in the A000 family, allowing to
support aggregations of 64 frames (rather than 63).

Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>