e1000e: fix runtime power management transitions

This patch removes redundant actions from driver and fixes its interaction
with actions in pci-bus runtime power management code.

It removes pci_save_state() from __e1000_shutdown() for normal adapters,
PCI bus callbacks pci_pm_*() will do all this for us. Now __e1000_shutdown()
switches to D3-state only quad-port adapters, because they needs quirk for
clearing false-positive error from downsteam pci-e port.

pci_save_state() now called after clearing bus-master bit, thus __e1000_resume()
and e1000_io_slot_reset() must set it back after restoring configuration space.

This patch set get_link_status before calling pm_runtime_put() in e1000_open()
to allow e1000_idle() get real link status and schedule first runtime suspend.

This patch also enables wakeup for device if management mode is enabled
(like for WoL) as result pci_prepare_to_sleep() would setup wakeup without
special actions like custom 'enable_wakeup' sign.

Cc: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Borislav Petkov <bp@suse.de>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>