drm/i915: Remove redundant queue_delayed_work() from throttle ioctl

We know, by design, that whilst the GPU is active (and thus we are
throttling) the retire_worker is queued. Therefore attempting to requeue
it with queue_delayed_work() is a no-op and we can safely remove it.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1467616119-4093-3-git-send-email-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gem.c

@@ -4467,9 +4467,6 @@ i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file)
 		return 0;
 
 	ret = __i915_wait_request(target, true, NULL, NULL);
-	if (ret == 0)
-		queue_delayed_work(dev_priv->wq, &dev_priv->gt.retire_work, 0);
-
 	i915_gem_request_unreference(target);
 
 	return ret;