Revert "i965: Disable texture tiling by default."

This reverts commit b8e638d489.

Now that the known hangs and misrendering issues are fixed, I'm ready to
start encouraging it by default again.

src/mesa/drivers/dri/intel/intel_screen.c

@@ -69,7 +69,11 @@ PUBLIC const char __driConfigOptions[] =
 	 DRI_CONF_DESC_END
       DRI_CONF_OPT_END
 
-      DRI_CONF_TEXTURE_TILING(false)
+#ifdef I915
+     DRI_CONF_TEXTURE_TILING(false)
+#else
+     DRI_CONF_TEXTURE_TILING(true)
+#endif
 
       DRI_CONF_OPT_BEGIN(early_z, bool, false)
 	 DRI_CONF_DESC(en, "Enable early Z in classic mode (unstable, 945-only).")