Add git://git.kernel.org/pub/scm/docs/man-pages/man-pages.git submodule

  git submodule add \
    git://git.kernel.org/pub/scm/docs/man-pages/man-pages.git man-pages-git

Sync to upstream 32398a6.

Set V=3.52-git
Remove man-pages-git submodule and set V to 3.52
Merge remote-tracking branch 'upstream/master'