wifi: iwlwifi: mvm: revert gen2 TX A-MPDU size to 64

We don't actually support >64 even for HE devices, so revert
back to 64. This fixes an issue where the session is refused
because the queue is configured differently from the actual
session later.

Fixes: 514c3069

 ("iwlwifi: add support for IEEE802.11ax")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Liad Kaufman <liad.kaufman@intel.com>
Reviewed-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240510170500.52f7b4cf83aa.If47e43adddf7fe250ed7f5571fbb35d8221c7c47@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>