maps/ipcache: Refactor path name for map
maps/ipcache: Refactor path name for map

An upcoming commit will need to open an ipcache at a non-standard path
on the filesystem. To support this, factor out the name to be used for
the map on the filesystem and force the user to specify it when creating
the IPCache map.

Signed-off-by: Joe Stringer <16a9a54ddf4259952e3c118c763138e83693d7fd@covalent.io>

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