datapath/iptables: use constants for host devices
datapath/iptables: use constants for host devices

Use the constants from pkg/defaults instead of hard-coding
cilium_{host,net}.

Signed-off-by: Tobias Klauser <059b8b880f8441509ec8a65b50b4c6ae74ebea76@cilium.io>

michi-covalent/cilium,michi-covalent/cilium,cilium/cilium,cilium/cilium,cilium/cilium,michi-covalent/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium