drm/vboxvideo: Use managed VRAM-helper initialization

updated to use drmm_vram_helper_init().
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1614735587-6621-1-git-send-email-tiantao6@hisilicon.com

drivers/gpu/drm/vboxvideo/vbox_ttm.c

@@ -12,15 +12,13 @@
 
 int vbox_mm_init(struct vbox_private *vbox)
 {
-	struct drm_vram_mm *vmm;
 	int ret;
 	struct drm_device *dev = &vbox->ddev;
 	struct pci_dev *pdev = to_pci_dev(dev->dev);
 
-	vmm = drm_vram_helper_alloc_mm(dev, pci_resource_start(pdev, 0),
+	ret = drmm_vram_helper_init(dev, pci_resource_start(pdev, 0),
 				       vbox->available_vram_size);
-	if (IS_ERR(vmm)) {
-		ret = PTR_ERR(vmm);
+	if (ret) {
 		DRM_ERROR("Error initializing VRAM MM; %d\n", ret);
 		return ret;
 	}
@@ -33,5 +31,4 @@ int vbox_mm_init(struct vbox_private *vbox)
 void vbox_mm_fini(struct vbox_private *vbox)
 {
 	arch_phys_wc_del(vbox->fb_mtrr);
-	drm_vram_helper_release_mm(&vbox->ddev);
 }