sky2: fix Wake On Lan interaction with BIOS

This patch disables config mode access after clearing PCI settings.
Some BIOS's seem to not do WOL if config bit still set.

Fixes: http://bugzilla.kernel.org/show_bug.cgi?id=9721



Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: David S. Miller <davem@davemloft.net>