More fixups for orb_advert_t changed to void *

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

src/modules/mavlink/mavlink_mission.cpp

@@ -81,7 +81,7 @@ MavlinkMissionManager::MavlinkMissionManager(Mavlink *mavlink) : MavlinkStream(m
 	_transfer_partner_compid(0),
 	_offboard_mission_sub(-1),
 	_mission_result_sub(-1),
-	_offboard_mission_pub(0),
+	_offboard_mission_pub(nullptr),
 	_slow_rate_limiter(_interval / 10.0f),
 	_verbose(false)
 {

src/modules/mavlink/mavlink_parameters.cpp

@@ -45,7 +45,7 @@
 
 MavlinkParametersManager::MavlinkParametersManager(Mavlink *mavlink) : MavlinkStream(mavlink),
 	_send_all_index(-1),
-	_rc_param_map_pub(0),
+	_rc_param_map_pub(nullptr),
 	_rc_param_map()
 {
 }