i965: Use miptree_create_for_dri_image in image_target_renderbuffer_storage

This does make a tiny functional change in that we now also test for
whether or not the format supports texturing and not just rendering.
However, this should have no practical effect as all renderbuffers use
texturable formats.

Reviewed-by: Chad Versace <chadversary@chromium.org>

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

@@ -362,31 +362,10 @@ intel_image_target_renderbuffer_storage(struct gl_context *ctx,
     * buffer's content to the main buffer nor for invalidating the aux buffer's
     * content.
     */
-   irb->mt = intel_miptree_create_for_bo(brw,
-                                         image->bo,
-                                         image->format,
-                                         image->offset,
-                                         image->width,
-                                         image->height,
-                                         1,
-                                         image->pitch,
-                                         MIPTREE_LAYOUT_DISABLE_AUX);
+   irb->mt = intel_miptree_create_for_dri_image(brw, image, GL_TEXTURE_2D);
    if (!irb->mt)
       return;
 
-   /* Adjust the miptree's upper-left coordinate.
-    *
-    * FIXME: Adjusting the miptree's layout outside of
-    * intel_miptree_create_layout() is fragile. Plumb the adjustment through
-    * intel_miptree_create_layout() and brw_tex_layout().
-    */
-   irb->mt->level[0].level_x = image->tile_x;
-   irb->mt->level[0].level_y = image->tile_y;
-   irb->mt->level[0].slice[0].x_offset = image->tile_x;
-   irb->mt->level[0].slice[0].y_offset = image->tile_y;
-   irb->mt->total_width += image->tile_x;
-   irb->mt->total_height += image->tile_y;
-
    rb->InternalFormat = image->internal_format;
    rb->Width = image->width;
    rb->Height = image->height;