This patch adds workaround to fix performance problems caused by slow
PCIE L1->L0 transitions on ICH8 platforms.

Changed all magic numbers to constants as suggested by Jeff Garzik.
Signed-off-by: NMatt Carlson <mcarlson@broadcom.com>
Signed-off-by: NMichael Chan <mchan@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>