Merge branch 'bpf-lpm-get-next-key'

Merge branch 'bpf-lpm-get-next-key'

Yonghong Song says:

====================
This patch set implements MAP_GET_NEXT_KEY command for LPM_TRIE map.
This command is really useful for key enumeration, and for key deletion
if what keys in the trie are unknown.

Patch #1 implements the functionality in the kernel and patch #2
adds a test case in tools/testing/selftests/bpf.
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>