tools headers uapi: Sync linux/stat.h with the kernel sources to pick STATX_MNT_ID_UNIQUE

tools headers uapi: Sync linux/stat.h with the kernel sources to pick STATX_MNT_ID_UNIQUE

To pick the changes from:

  98d2b43081972abe ("add unique mount ID")

That add STATX_MNT_ID_UNIQUE that was manually added to
tools/perf/trace/beauty/statx.c, at some point this should move to the
shell based automated way.

This silences this perf build warning:

  Warning: Kernel ABI header differences:
    diff -u tools/include/uapi/linux/stat.h include/uapi/linux/stat.h

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/lkml/ZbJq08s19890WDo-@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>