ioctl_userfaultfd.2: Add UFFD_FEATURE_THREAD_ID docs

UFFD_FEATURE_THREAD_ID is supported in Linux 4.14.

Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
1 file changed