Revert "drm/mediatek: set vblank_disable_allowed to true"

This reverts commit f752fff611b99f5679224f3990a1f531ea64b1ec.

Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index 0b2ae47..cf83f65 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
@@ -217,7 +217,6 @@
 	if (ret < 0)
 		goto err_component_unbind;
 
-	drm->vblank_disable_allowed = true;
 	drm_kms_helper_poll_init(drm);
 	drm_mode_config_reset(drm);