Switch to using typesafe kernel ebpf map accessors

Test: atest libbpf_android_test libnetdbpf_test netd_integration_test netd_unit_test netdutils_test resolv_integration_test resolv_unit_test
Bug: 130746652
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I1a2e8fe1bdf0914a90902666895705b45fd1f959