atomic-implement-generic-atomic_dec_if_positive-fix

atomic-implement-generic-atomic_dec_if_positive-fix

do the "#define foo foo" trick in the conventional manner

Cc: "David S. Miller" <davem@davemloft.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@fusionio.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>