i965/gen7: Fix miptree layout for cube surfaces.

Volume 1a section 8.20.4.7.3 gives new equations which multiply by 12
instead of 11.

Fixes 8 piglit tests:
- fbo-cubemap
- texCube
- glsl-fs-texturecube
- glsl-fs-texturecube-2
- glsl-fs-texturecube-2-bias
- glsl-fs-texturecube-bias
- arb_seamless_cubemap
- cubemap

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>

src/mesa/drivers/dri/i965/brw_tex_layout.c

@@ -61,7 +61,7 @@ GLboolean brw_miptree_layout(struct intel_context *intel,
 	   */
 	  h0 = ALIGN(mt->height0, align_h);
 	  h1 = ALIGN(minify(h0), align_h);
-	  qpitch = (h0 + h1 + 11 * align_h);
+	  qpitch = (h0 + h1 + (intel->gen >= 7 ? 12 : 11) * align_h);
           if (mt->compressed)
 	     qpitch /= 4;