logger: Log GPS drift data

This data is published at the GPS publication rate and only when on ground.

src/modules/logger/logger.cpp

@@ -614,6 +614,7 @@ void Logger::add_default_topics()
 	add_topic("cpuload");
 	add_topic("distance_sensor", 100);
 	add_topic("ekf2_innovations", 200);
+	add_topic("ekf_gps_drift");
 	add_topic("esc_status", 250);
 	add_topic("estimator_status", 200);
 	add_topic("home_position");