Pull xen fixes from Juergen Gross:
 "This contains two build fixes for clang and two fixes for rather
  unlikely situations in the Xen gntdev driver"

* tag 'for-linus-4.15-rc8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/gntdev: Fix partial gntdev_mmap() cleanup
  xen/gntdev: Fix off-by-one error when unmapping with holes
  x86: xen: remove the use of VLAIS
  x86/xen/time: fix section mismatch for xen_init_time_ops()