drm/i915: Remove stale code

Looks like a some remnant from a rebase.
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -815,7 +815,6 @@ int i915_gem_gtt_init(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct i915_gtt *gtt = &dev_priv->gtt;
-	unsigned long gtt_size;
 	int ret;
 
 	if (INTEL_INFO(dev)->gen <= 5) {
@@ -833,8 +832,6 @@ int i915_gem_gtt_init(struct drm_device *dev)
 	if (ret)
 		return ret;
 
-	gtt_size = (dev_priv->gtt.total >> PAGE_SHIFT) * sizeof(gen6_gtt_pte_t);
-
 	/* GMADR is the PCI mmio aperture into the global GTT. */
 	DRM_INFO("Memory usable by graphics device = %zdM\n",
 		 dev_priv->gtt.total >> 20);