intel: Add and use max_constant_urb_size_kb

This knowledge was repeated in multiple places so move the values to
intel_device_info struct.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Acked-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13014>

src/intel/dev/intel_device_info_test.c

@@ -28,6 +28,8 @@ main(int argc, char *argv[])
       assert(devinfo.num_thread_per_eu != 0);
       assert(devinfo.timestamp_frequency != 0);
       assert(devinfo.cs_prefetch_size > 0);
+
+      assert(devinfo.ver < 7 || devinfo.max_constant_urb_size_kb > 0);
    }
 
    return 0;