drm/i915: fix rc6 enabling around suspend/resume

Enabling RC6 implies setting a graphics context.  Make sure we do that
only after the ring has been enabled, otherwise our ring commands will
hang.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 2913496..02fce7f 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -357,6 +357,9 @@
 		drm_helper_resume_force_mode(dev);
 	}
 
+	/* Clock gating state */
+	intel_enable_clock_gating(dev);
+
 	intel_opregion_init(dev);
 
 	dev_priv->modeset_on_lid = 0;