tools: sync uapi/linux/fs.h header into tools subdir

We need this UAPI header in tools/include subdirectory for using it from
BPF selftests.

Link: https://lkml.kernel.org/r/20240627170900.1672542-6-andrii@kernel.org


Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>