vulkan: Fix 32-bit build for the new overlay layer

vulkan: Fix 32-bit build for the new overlay layer

vulkan_core.h defines non-dispatchable handles as (struct object *)
on 64-bit systems, but uint64_t on 32-bit systems.  The former can be
implicitly cast to void *, but the latter requires an explicit cast.

While here, %lu is the wrong format specifier for uint64_t on 32-bit
systems, so use PRIu64, fixing a warning.

Reported-by: Mike Lothian <mike@fireburn.co.uk>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>