Merge tag 'stable/for-linus-3.17-b-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull Xen bugfixes from David Vrabel:
 - fix ARM build
 - fix boot crash with PVH guests
 - improve reliability of resume/migration

* tag 'stable/for-linus-3.17-b-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  x86/xen: use vmap() to map grant table pages in PVH guests
  x86/xen: resume timer irqs early
  arm/xen: remove duplicate arch_gnttab_init() function