PCI: clearing wakeup flags not needed

This patch (as1353) removes a couple of unnecessary assignments from
the PCI core.  The should_wakeup flag is naturally initialized to 0;
there's no need to clear it.

Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>