Makefile: merge same calls to generate k8s deepcopy code
Makefile: merge same calls to generate k8s deepcopy code

k8s deepcopy generator can have multiple groups for the same version
passed as a parameter. To speed up the code generation we can merge all
of them together.

The amount of time decreased from 50s to 16s.

Signed-off-by: André Martins <bc9800b9d52a24cce72a73dd528afed53f10e5fc@cilium.io>

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