intel: Add support for tiled textures.

This is about a 30% performance win in OA with high settings on my GM45,
and experiments with 915GM indicate that it'll be around a 20% win there.
Currently, 915-class hardware is seriously hurt by the fact that we use
fence regs to control the tiling even for 3D instructions that could live
without them, so we spend a bunch of time waiting on previous rendering in
order to pull fences off.  Thus, the texture_tiling driconf option defaults
off there for now.

src/mesa/drivers/dri/intel/intel_regions.h

@@ -73,7 +73,8 @@ struct intel_region
  * copied by calling intel_reference_region().
  */
 struct intel_region *intel_region_alloc(struct intel_context *intel,
-                                        GLuint cpp, GLuint width,
+                                        uint32_t tiling,
+					GLuint cpp, GLuint width,
                                         GLuint height, GLuint pitch,
 					GLboolean expect_accelerated_upload);