iwlwifi: always allow maximum A-MSDU on newer devices

On devices starting from 9000 series, always allow maximum A-MSDU
sizes regardless of the amsdu_size module parameter, which really
hasn't meant that for a long time but just controls the receive
buffer size.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210117164916.ebf6efb380a9.I237be6ec70bee6ec52a2f379ee1f15b1196488d0@changeid


Signed-off-by: Luca Coelho <luciano.coelho@intel.com>