drm/i915: Combine scratch members into a struct

There isn't any special reason to do this other than it makes it obvious
that the two members are connected.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index af8eadf..40bb23b 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -465,8 +465,10 @@
 	void __iomem *gsm;
 
 	bool do_idle_maps;
-	dma_addr_t scratch_page_dma;
-	struct page *scratch_page;
+	struct {
+		dma_addr_t addr;
+		struct page *page;
+	} scratch;
 
 	/* global gtt ops */
 	int (*gtt_probe)(struct drm_device *dev, size_t *gtt_total,