drm/i915: Mark i915_hpd_poll_init_work as static

Local function with forgotten static declaration.

Fixes: 19625e85 ("drm/i915: Enable polling when we don't have hpd")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Lyude <cpaul@redhat.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1471432146-5196-2-git-send-email-chris@chris-wilson.co.ukReviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

drivers/gpu/drm/i915/intel_hotplug.c

@@ -477,7 +477,8 @@ void intel_hpd_init(struct drm_i915_private *dev_priv)
 	spin_unlock_irq(&dev_priv->irq_lock);
 }
 
-void i915_hpd_poll_init_work(struct work_struct *work) {
+static void i915_hpd_poll_init_work(struct work_struct *work)
+{
 	struct drm_i915_private *dev_priv =
 		container_of(work, struct drm_i915_private,
 			     hotplug.poll_init_work);