SRV_Channels: unify singleton naming to _singleton and get_singleton()

libraries/SRV_Channel/SRV_Channel.h

@@ -471,7 +471,7 @@ private:
 
     // this static arrangement is to avoid having static objects in AP_Param tables
     static SRV_Channel *channels;
-    static SRV_Channels *instance;
+    static SRV_Channels *_singleton;
 
     // support for Volz protocol
     AP_Volz_Protocol volz;

libraries/SRV_Channel/SRV_Channel_aux.cpp

@@ -153,7 +153,7 @@ void SRV_Channels::update_aux_servo_function(void)
 /// Should be called after the the servo functions have been initialized
 void SRV_Channels::enable_aux_servos()
 {
-    hal.rcout->set_default_rate(uint16_t(instance->default_rate.get()));
+    hal.rcout->set_default_rate(uint16_t(_singleton->default_rate.get()));
 
     update_aux_servo_function();
 

libraries/SRV_Channel/SRV_Channels.cpp

@@ -36,7 +36,7 @@
 extern const AP_HAL::HAL& hal;
 
 SRV_Channel *SRV_Channels::channels;
-SRV_Channels *SRV_Channels::instance;
+SRV_Channels *SRV_Channels::_singleton;
 AP_Volz_Protocol *SRV_Channels::volz_ptr;
 AP_SBusOut *SRV_Channels::sbus_ptr;
 AP_RobotisServo *SRV_Channels::robotis_ptr;
@@ -160,7 +160,7 @@ const AP_Param::GroupInfo SRV_Channels::var_info[] = {
  */
 SRV_Channels::SRV_Channels(void)
 {
-    instance = this;
+    _singleton = this;
     channels = obj_channels;
 
     // set defaults from the parameter table