drm/i915: Silence sparse over non-static local structure.

drivers/gpu/drm/i915/i915_drv.c|485 col 25| warning: symbol 'i915_pm_ops' was not declared. Should it be static?
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/i915_drv.c

@@ -482,7 +482,7 @@ static int i915_pm_poweroff(struct device *dev)
 	return i915_drm_freeze(drm_dev);
 }
 
-const struct dev_pm_ops i915_pm_ops = {
+static const struct dev_pm_ops i915_pm_ops = {
      .suspend = i915_pm_suspend,
      .resume = i915_pm_resume,
      .freeze = i915_pm_freeze,