drm/i915: gen6_gmch_remove can be static

Signed-off-by: NChanglong Xie <changlongx.xie@intel.com>
Reported-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -773,7 +773,7 @@ static int gen6_gmch_probe(struct drm_device *dev,
 	return ret;
 }
 
-void gen6_gmch_remove(struct drm_device *dev)
+static void gen6_gmch_remove(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	iounmap(dev_priv->gtt.gsm);