intel/blorp: Add an "enabled" bit to surface_info

This gives a slightly smarter way to check whether or not a particular
surface exists than looking at the address.

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>

src/intel/blorp/blorp.c

@@ -64,6 +64,8 @@ brw_blorp_surface_info_init(struct blorp_context *blorp,
                             unsigned int level, unsigned int layer,
                             enum isl_format format, bool is_render_target)
 {
+   info->enabled = true;
+
    if (format == ISL_FORMAT_UNSUPPORTED)
       format = surf->surf->format;