perfctr-watchdog: fix interchanged parameters to release_{evntsel,perfctr}_nmi

Fix oops triggered during: echo 0 > /proc/sys/kernel/nmi_watchdog

The culprit seems to be 09198e68:
[PATCH] i386: Clean up NMI watchdog code

In two places, the parameters to release_{evntsel,perfctr}_nmi
got interchanged during the cleanup.

Fix interchanged parameters to release_{evntsel,perfctr}_nmi.

Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de>
Cc: Stephane Eranian <eranian@hpl.hp.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>