tools headers: Sync UAPI linux/fs.h with the kernel sources

To pick up the changes in:

  45e57cfb7b10b64f ("fs: Clarify FS_CASEFOLD_FL semantics in UAPI header")

That don't result in changes to the string tables generated from this header.

This addresses this perf build warning:

  Warning: Kernel ABI header differences:
    diff -u tools/perf/trace/beauty/include/uapi/linux/fs.h include/uapi/linux/fs.h

Please see tools/include/uapi/README for further details.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>