e100: Use pci_pme_active to clear PME_Status and disable PME#

Currently e100 uses pci_enable_wake() to clear pending wake-up events
and disable PME# during intitialization, but that function is not
suitable for this purpose, because it immediately returns error code
if device_may_wakeup() returns false for given device.

Make e100 use pci_pme_active(), which carries out exactly the
required operations, instead.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>