wifi: iwlwifi: mvm: properly set 6 GHz channel direct probe option

Ensure that the 6 GHz channel is configured with a valid direct BSSID,
avoiding any invalid or multicast BSSID addresses.

Signed-off-by: Ayala Beker <ayala.beker@intel.com>
Reviewed-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240513132416.91a631a0fe60.I2ea2616af9b8a2eaf959b156c69cf65a2f1204d4@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>