iwlwifi: add some missing kernel-doc in struct iwl_fw

The phy integration string members were missed, add them.

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.20211017113927.8aa65feeda5f.Idf492c939f7f8856da09c5017c16b8b88438395d@changeid


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