mm: remove memcg oom killer sync up with upstream

mm: remove memcg oom killer sync up with upstream

This memcg oom killer code was removed in upstream stable tree, but
still keep that. After enabling CONFIG_MEMCG in kernel, kernel booting
will give endless warning and system is not usable.

This patch fix this issue and it's required for using Docker on L4T

Bug 1767148

Change-Id: I50e60c7cd8e60fd1d757597d9260a9bee806e292
Signed-off-by: Bryan Wu <pengw@nvidia.com>
Reviewed-on: http://git-master/r/1171277
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>