While UINTN defined for RISC-V 64 bits is UINT64, explictly using UINT64 for those variables that clearly are UINT64. Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: Laszlo Ersek <lersek@redhat.com> Cc: Rahul Kumar <rahul1.kumar@intel.com> Cc: Ray Ni <ray.ni@intel.com> Signed-off-by: Tuan Phan <tphan@ventanamicro.com> Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>