Documentation/locking/lockdep: Drop last two chars of sample states

Since the removal of FS_RECLAIM annotations, lockdep states contain four
characters, not six.

Fixes: e5684bbf ("Documentation/locking/lockdep: Update info about states")
Fixes: d92a8cfc ("locking/lockdep: Rework FS_RECLAIM annotation")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>