The code blindly assumes a TIS interface is present in case both CRB and
FIFO checks fail. Check the InterfaceType for TIS instead and only
return PtpInterfaceTis in case it matches, PtpInterfaceMax otherwise.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>