BpfMap.getOrCreate(size, path, type) -> BpfMap.init(path)

We don't have the appropriate selinux privs to create the maps anyway.

Test: builds (when combined with system/bpf change)
      atest netd_unit_test netd_integration_test
Bug: 65674744
Bug: 129654883
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I07259669ff73352311a1f8dbda170ef2cfde2890