Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild

Pull kbuild update from Michal Marek:
 "The kbuild branch for v4.4-rc1 only has one commit: A new make
  kselftest-clean target cleans tools/testing/selftests"

* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  kselftest: add kselftest-clean rule