endpoint: do not compute L4Policy when enforcement disabled
endpoint: do not compute L4Policy when enforcement disabled

If policy enforcement is not enabled in a given traffic direction for an
endpoint, there is no need to iterate over the policy repository to find rules
which select the endpoint, because it is already known that the policy
repository at that time does not have any rules which select it.

Signed-off by: Ian Vernon <ian@cilium.io>

scanf/cilium,scanf/cilium,scanf/cilium,tgraf/cilium,tgraf/cilium,tklauser/cilium,michi-covalent/cilium,tgraf/cilium,tklauser/cilium,michi-covalent/cilium,scanf/cilium,tgraf/cilium,cilium-team/cilium,cilium/cilium,cilium/cilium,scanf/cilium,cilium-team/cilium,tklauser/cilium,tklauser/cilium,michi-covalent/cilium,tgraf/cilium,michi-covalent/cilium,tgraf/cilium,cilium/cilium,tklauser/cilium,michi-covalent/cilium,scanf/cilium,cilium/cilium,cilium/cilium,scanf/cilium