ioctl_userfaultfd.2, userfaultfd.2: Add description for UFFD_FEATURE_SIGBUS

Userfaultfd feature UFFD_FEATURE_SIGBUS was merged recently and
should be available in the Linux 4.14 release. This patch is for
the man page changes documenting this API.

Documents the following commit:

commit 2d6d6f5a09a96cc1fec7ed992b825e05f64cb50e
Author: Prakash Sangappa <prakash.sangappa@oracle.com>
Date: Wed Sep 6 16:23:39 2017 -0700

     mm: userfaultfd: add feature to request for a signal delivery

Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Prakash Sangappa <prakash.sangappa@oracle.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2 files changed