Manually apply white channel to array

quantum/rgblight.c

@@ -625,7 +625,9 @@ void rgblight_set(void) {
 #    endif
 
 #ifdef RGBW
-    convert_rgb_to_rgbw(start_led);
+    for (uint8_t i = 0; i < num_leds; i++) {
+        convert_rgb_to_rgbw(start_led[i]);
+    }
 #endif
    ws2812_setleds(start_led, num_leds);
 }