Revert "drm/i915: Don't skip request retirement if the active list is empty"

This reverts commit 0aedb162.

I messed things up while applying [1] to drm-intel-fixes. Rectify.

[1] http://mid.gmane.org/1432827156-9605-1-git-send-email-ville.syrjala@linux.intel.com

Fixes: 0aedb162 ("drm/i915: Don't skip request retirement if the active list is empty")
Cc: stable@vger.kernel.org
Acked-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/i915_gem.c

@@ -2656,6 +2656,9 @@ void i915_gem_reset(struct drm_device *dev)
 void
 i915_gem_retire_requests_ring(struct intel_engine_cs *ring)
 {
+	if (list_empty(&ring->request_list))
+		return;
+
 	WARN_ON(i915_verify_lists(ring->dev));
 
 	/* Retire requests first as we use it above for the early return.