Merge branch 'stable/frontswap-tmemonly' of git://git.kernel.org/pub/scm/linux/kernel/git/djm/tmem into stable/drivers

* 'stable/frontswap-tmemonly' of git://git.kernel.org/pub/scm/linux/kernel/git/djm/tmem:
  xen: prepare tmem shim to handle frontswap