listener: add note for old reuse port compatible code (#20128)
listener: add note for old reuse port compatible code (#20128)

Signed-off-by: He Jie Xu <0fe0bd399dd39b6e2574442cf896a57f5611d8c7@intel.com>
envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy