drm/sti: Don't call drm_helper_disable_unused_functions

Atomic drivers are supposed to do hw/sw state reset with the
drm_mode_config_reset() call right above it.

Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Acked-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1464818821-5736-38-git-send-email-daniel.vetter@ffwll.ch
diff --git a/drivers/gpu/drm/sti/sti_drv.c b/drivers/gpu/drm/sti/sti_drv.c
index dd2c400..26aa85d 100644
--- a/drivers/gpu/drm/sti/sti_drv.c
+++ b/drivers/gpu/drm/sti/sti_drv.c
@@ -279,7 +279,6 @@
 
 	drm_mode_config_reset(dev);
 
-	drm_helper_disable_unused_functions(dev);
 	drm_fbdev_cma_init(dev, 32,
 			   dev->mode_config.num_crtc,
 			   dev->mode_config.num_connector);