common: remove unused func FindEPConfigCHeader
common: remove unused func FindEPConfigCHeader

This was already removed by commit d81a5cdea511 ("pkg/endpoint: Simplify
search for C header file") when its last user disappeard, but it got
readded 74e706da2d9e ("common: Move GoArray2C to common") which moved
some code around the same time. Now remove it for good.

Fixes: 74e706da2d9e ("common: Move GoArray2C to common")
Signed-off-by: Tobias Klauser <9249c549618448e4c699e8032ba6c7f0d7fd4b7f@distanz.ch>

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