x86: spinlock.h: Remove REG_PTR_MODE

REG_PTR_MODE has no users at all.

Signed-off-by: Richard Weinberger <richard@nod.at>
Link: http://lkml.kernel.org/r/1333064283-3109-1-git-send-email-richard@nod.at


Acked-by: Acked-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>