Add init function to RGBLight driver struct (#23076)

quantum/rgblight/rgblight_drivers.c

@@ -7,6 +7,7 @@
 #    include "ws2812.h"
 
 const rgblight_driver_t rgblight_driver = {
+    .init    = ws2812_init,
     .setleds = ws2812_setleds,
 };
 
@@ -14,6 +15,7 @@ const rgblight_driver_t rgblight_driver = {
 #    include "apa102.h"
 
 const rgblight_driver_t rgblight_driver = {
+    .init    = apa102_init,
     .setleds = apa102_setleds,
 };