AP_Notify: RGB LED remove unused varables

libraries/AP_Notify/RGBLed.cpp

@@ -220,11 +220,11 @@ void RGBLed::update()
 
     const uint8_t colour = (current_colour_sequence >> (step*3)) & 7;
 
-    _red_des = (colour & RED) ? brightness : _led_off;
-    _green_des = (colour & GREEN) ? brightness : _led_off;
-    _blue_des = (colour & BLUE) ? brightness : _led_off;
+    uint8_t red_des = (colour & RED) ? brightness : _led_off;
+    uint8_t green_des = (colour & GREEN) ? brightness : _led_off;
+    uint8_t blue_des = (colour & BLUE) ? brightness : _led_off;
 
-    set_rgb(_red_des, _green_des, _blue_des);
+    set_rgb(red_des, green_des, blue_des);
 }
 
 /*

libraries/AP_Notify/RGBLed.h

@@ -54,7 +54,6 @@ protected:
     void update_override();
     
     // meta-data common to all hw devices
-    uint8_t _red_des, _green_des, _blue_des;     // color requested by timed update
     uint8_t _red_curr, _green_curr, _blue_curr;  // current colours displayed by the led
     uint8_t _led_off;
     uint8_t _led_bright;