drm/i915: Remove scratch page from shared

We already had a mapping in both (minus the phys_addr in AGP).

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -383,6 +383,8 @@ struct i915_gtt {
 	void __iomem *gsm;
 
 	bool do_idle_maps;
+	dma_addr_t scratch_page_dma;
+	struct page *scratch_page;
 };
 
 #define I915_PPGTT_PD_ENTRIES 512