iwlwifi: bump FW API to 60 for AX devices

Start supporting API version 60 for AX devices.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210205110447.7b908f5dd970.Id2aec0d7d33921aba77ba9853196f81d5950c31c@changeid


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