ArduCopter: log GPS primary change event in GPS library

ArduCopter/Copter.h

@@ -405,7 +405,6 @@ private:
     struct {
         uint8_t baro        : 1;    // true if baro is healthy
         uint8_t compass     : 1;    // true if compass is healthy
-        uint8_t primary_gps : 2;    // primary gps index
     } sensor_health;
 
     // Motor Output

ArduCopter/Log.cpp

@@ -265,12 +265,6 @@ void Copter::Log_Sensor_Health()
         sensor_health.compass = compass.healthy();
         AP::logger().Write_Error(LogErrorSubsystem::COMPASS, (sensor_health.compass ? LogErrorCode::ERROR_RESOLVED : LogErrorCode::UNHEALTHY));
     }
-
-    // check primary GPS
-    if (sensor_health.primary_gps != gps.primary_sensor()) {
-        sensor_health.primary_gps = gps.primary_sensor();
-        AP::logger().Write_Event(LogEvent::GPS_PRIMARY_CHANGED);
-    }
 }
 
 struct PACKED log_SysIdD {