iwlwifi: bump FW API to 64 for AX devices

Start supporting API version 64 for AX devices.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210621103449.8144a5b7d9a7.Ibf77fd7daa7d22f7c46d1c4a572ab9441a761299@changeid


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