Fix macro in set_color() (#13417)

Marlin/src/feature/leds/leds.cpp

 
     // This variant uses 3-4 separate pins for the RGB(W) components.
     // If the pins can do PWM then their intensity will be set.
-    #define UPDATE_RGBW(C,c) do{ if (PWM_PIN(RGB_LED_##C##_PIN)) analogWrite(RGB_LED_##C##_PIN, incol.r); else WRITE(RGB_LED_##C##_PIN, incol.c ? HIGH : LOW); }while(0)
+    #define UPDATE_RGBW(C,c) do{ if (PWM_PIN(RGB_LED_##C##_PIN)) analogWrite(RGB_LED_##C##_PIN, incol.c); else WRITE(RGB_LED_##C##_PIN, incol.c ? HIGH : LOW); }while(0)
     UPDATE_RGBW(R,r);
     UPDATE_RGBW(G,g);
     UPDATE_RGBW(B,b);