drm/vboxvideo: Use drm_gem_fb_create_with_dirty instead of drm_gem_fb_create

Commit 7d79aa86 ("drm/vboxvideo: Replace struct vram_framebuffer
with generic implemenation") removed the diy framebuffer code from
the vboxvideo driver, resulting in a nice cleanup.

But since the vboxvideo driver needs the generic dirty tracking code,
it's drm_mode_config_funcs.fb_create should be set to
drm_gem_fb_create_with_dirty not drm_gem_fb_create.

This commit fixes this, fixing the framebuffer not always updating.

Cc: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 7d79aa86 ("drm/vboxvideo: Replace struct vram_framebuffer with generic implemenation")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20191028133159.236550-1-hdegoede@redhat.com

drivers/gpu/drm/vboxvideo/vbox_mode.c

@@ -837,7 +837,7 @@ static int vbox_connector_init(struct drm_device *dev,
 }
 
 static const struct drm_mode_config_funcs vbox_mode_funcs = {
-	.fb_create = drm_gem_fb_create,
+	.fb_create = drm_gem_fb_create_with_dirty,
 	.atomic_check = drm_atomic_helper_check,
 	.atomic_commit = drm_atomic_helper_commit,
 };