tools include UAPI: Update linux/mount.h copy

To pick the changes from:

  9ffb14ef61bab83f ("move_mount: allow to add a mount into an existing group")

That ends up adding support for the new MOVE_MOUNT_SET_GROUP move_mount
flag.

  $ tools/perf/trace/beauty/move_mount_flags.sh > before
  $ cp include/uapi/linux/mount.h tools/include/uapi/linux/mount.h
  $ tools/perf/trace/beauty/move_mount_flags.sh > after
  $ diff -u before after
  --- before	2021-09-10 12:28:43.865279808 -0300
  +++ after	2021-09-10 12:28:50.183429184 -0300
  @@ -5,4 +5,5 @@
   	[ilog2(0x00000010) + 1] = "T_SYMLINKS",
   	[ilog2(0x00000020) + 1] = "T_AUTOMOUNTS",
   	[ilog2(0x00000040) + 1] = "T_EMPTY_PATH",
  +	[ilog2(0x00000100) + 1] = "SET_GROUP",
   };
  $

So now one can use it in --filter expressions for tracepoints.

This silences this perf build warnings:

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

Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>