drm/mediatek: Remove dependency on GEM DMA helper

It appears that the dependency on the DMA helpers was only for
drm_gem_dma_vm_ops.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20230119224052.2879106-1-robdclark@gmail.com/Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

drivers/gpu/drm/mediatek/Kconfig

@@ -7,7 +7,6 @@ config DRM_MEDIATEK
 	depends on HAVE_ARM_SMCCC
 	depends on OF
 	depends on MTK_MMSYS
-	select DRM_GEM_DMA_HELPER
 	select DRM_KMS_HELPER
 	select DRM_MIPI_DSI
 	select DRM_PANEL

drivers/gpu/drm/mediatek/mtk_drm_gem.c

@@ -16,13 +16,18 @@
 
 static int mtk_drm_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
 
+static const struct vm_operations_struct vm_ops = {
+	.open = drm_gem_vm_open,
+	.close = drm_gem_vm_close,
+};
+
 static const struct drm_gem_object_funcs mtk_drm_gem_object_funcs = {
 	.free = mtk_drm_gem_free_object,
 	.get_sg_table = mtk_gem_prime_get_sg_table,
 	.vmap = mtk_drm_gem_prime_vmap,
 	.vunmap = mtk_drm_gem_prime_vunmap,
 	.mmap = mtk_drm_gem_object_mmap,
-	.vm_ops = &drm_gem_dma_vm_ops,
+	.vm_ops = &vm_ops,
 };
 
 static struct mtk_drm_gem_obj *mtk_drm_gem_init(struct drm_device *dev,