wifi: iwlwifi: mvm: Handle BIGTK cipher in kek_kck cmd

The BIGTK cipher field was added to the kek_kck_material_cmd
but wasn't assigned. Fix that by differentiating between the
IGTK/BIGTK keys and assign the ciphers fields accordingly.

Signed-off-by: Yedidya Benshimol <yedidya.ben.shimol@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240513132416.7fd0b22b7267.Ie9b581652b74bd7806980364d59e1b2e78e682c0@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>