SecurityPkg/HashLibTdx: Return EFI_UNSUPPORTED if it is not Tdx guest
HashLibTdx is designed for the Tdx guest. So if is not a Tdx guest,
return EFI_UNSUPPORTED in RegisterHashInterfaceLib.
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>