drm/i915: make hw page ioremap use ioremap_wc

However we still have another issue with ioremap_wc not falling back
properly or somehow doing something else stupid, this probably needs
to be tracked down.
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/i915/i915_dma.c

@@ -811,7 +811,7 @@ static int i915_set_status_page(struct drm_device *dev, void *data,
 	dev_priv->hws_map.flags = 0;
 	dev_priv->hws_map.mtrr = 0;
 
-	drm_core_ioremap(&dev_priv->hws_map, dev);
+	drm_core_ioremap_wc(&dev_priv->hws_map, dev);
 	if (dev_priv->hws_map.handle == NULL) {
 		i915_dma_cleanup(dev);
 		dev_priv->status_gfx_addr = 0;