bfd: register udp ports only when enabled
bfd: register udp ports only when enabled

Change-Id: Iffb4b314be3ded0d9c6acb77ec1c6f22778f301d
Signed-off-by: Klement Sekera <b8003f27414ca85c37624503b7b4e8f8c829bb4d@cisco.com>

chrisy/vpp,vpp-dev/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,vpp-dev/vpp,chrisy/vpp,chrisy/vpp,vpp-dev/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,vpp-dev/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,vpp-dev/vpp,FDio/vpp,FDio/vpp,vpp-dev/vpp,FDio/vpp,vpp-dev/vpp