Clean up some register constant use

src/field_screen_effect.c

@@ -56,7 +56,7 @@ const s32 gMaxFlashLevel = ARRAY_COUNT(sFlashLevelPixelRadii) - 1;
 
 const struct ScanlineEffectParams sFlashEffectParams =
 {
-    (void *)REG_ADDR_WIN0H,
+    &REG_WIN0H,
     ((DMA_ENABLE | DMA_START_HBLANK | DMA_REPEAT | DMA_DEST_RELOAD) << 16) | 1,
     1
 };