More fixups for orb_advert_t changed to void *

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

src/drivers/hil/hil.cpp

@@ -805,7 +805,7 @@ fake(int argc, char *argv[])
 
 	orb_advert_t handle = orb_advertise(ORB_ID_VEHICLE_ATTITUDE_CONTROLS, &ac);
 
-	if (handle == 0) {
+	if (handle == nullptr) {
 		puts("advertise failed");
 		return 1;
 	}

src/drivers/trone/trone.cpp

@@ -238,7 +238,7 @@ TRONE::TRONE(int bus, int address) :
 	_collect_phase(false),
 	_class_instance(-1),
 	_orb_class_instance(-1),
-	_distance_sensor_topic(0),
+	_distance_sensor_topic(nullptr),
 	_sample_perf(perf_alloc(PC_ELAPSED, "trone_read")),
 	_comms_errors(perf_alloc(PC_COUNT, "trone_comms_errors")),
 	_buffer_overflows(perf_alloc(PC_COUNT, "trone_buffer_overflows"))