aws/eni/limits: lazily populate limits map
aws/eni/limits: lazily populate limits map

The static limits map generated ~30kB on the heap at init time before,
regardless of whether limits were used. Avoid this by lazily populating
the map on first use.

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

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