drm: mediatek: use common helper for extracting pages array

Use common helper for converting a sg_table object into struct
page pointer array.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

drivers/gpu/drm/mediatek/mtk_drm_gem.c

@@ -233,9 +233,7 @@ void *mtk_drm_gem_prime_vmap(struct drm_gem_object *obj)
 {
 	struct mtk_drm_gem_obj *mtk_gem = to_mtk_gem_obj(obj);
 	struct sg_table *sgt;
-	struct sg_page_iter iter;
 	unsigned int npages;
-	unsigned int i = 0;
 
 	if (mtk_gem->kvaddr)
 		return mtk_gem->kvaddr;
@@ -249,11 +247,8 @@ void *mtk_drm_gem_prime_vmap(struct drm_gem_object *obj)
 	if (!mtk_gem->pages)
 		goto out;
 
-	for_each_sg_page(sgt->sgl, &iter, sgt->orig_nents, 0) {
-		mtk_gem->pages[i++] = sg_page_iter_page(&iter);
-		if (i > npages)
-			break;
-	}
+	drm_prime_sg_to_page_addr_arrays(sgt, mtk_gem->pages, NULL, npages);
+
 	mtk_gem->kvaddr = vmap(mtk_gem->pages, npages, VM_MAP,
 			       pgprot_writecombine(PAGE_KERNEL));