alpha: fix F_SETOWN_EX and F_GETLK64 conflict

Fix a bug in

    commit ba0a6c9f
    Author:     Peter Zijlstra <a.p.zijlstra@chello.nl>
    AuthorDate: Wed Sep 23 15:57:03 2009 -0700
    Commit:     Linus Torvalds <torvalds@linux-foundation.org>
    CommitDate: Thu Sep 24 07:21:01 2009 -0700

        fcntl: add F_[SG]ETOWN_EX

In asm-generic/fcntl.h, F_SETOWN_EX and F_GETLK64 both have value 12, and
F_GETOWN_EX and F_SETLK64 both have value 13.

Reported-by: "Joseph S. Myers" <joseph@codesourcery.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Andreas Schwab <schwab@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>