tools include UAPI: Sync linux/vhost.h with the kernel sources

To get the changes in:

  25abc060 ("vhost-vdpa: support IOTLB batching hints")

This doesn't result in any changes in tooling, no new ioctls to be
picked up by the id->string table generators, etc.

Silencing this perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/vhost.h' differs from latest version at 'include/uapi/linux/vhost.h'
  diff -u tools/include/uapi/linux/vhost.h include/uapi/linux/vhost.h

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>