Sub: Add method to uniformly scale the dead zones on all channels

ArduSub/joystick.cpp

@@ -203,18 +203,21 @@ void Sub::handle_jsbutton_press(uint8_t button, bool shift, bool held) {
 				} else {
 					gain = 1.0f;
 				}
+				RC_Channel::scale_dead_zones(gain);
 				gcs_send_text_fmt(MAV_SEVERITY_INFO,"#Gain: %2.0f%%",gain*100);
 			}
 			break;
 		case JSButton::button_function_t::k_gain_inc:
 			if ( !held ) {
 				gain = constrain_float(gain + (maxGain-minGain)/(numGainSettings-1), minGain, maxGain);
+				RC_Channel::scale_dead_zones(gain);
 				gcs_send_text_fmt(MAV_SEVERITY_INFO,"#Gain is %2.0f%%",gain*100);
 			}
 			break;
 		case JSButton::button_function_t::k_gain_dec:
 			if ( !held ) {
 				gain = constrain_float(gain - (maxGain-minGain)/(numGainSettings-1), minGain, maxGain);
+				RC_Channel::scale_dead_zones(gain);
 				gcs_send_text_fmt(MAV_SEVERITY_INFO,"#Gain is %2.0f%%",gain*100);
 			}
 			break;