[PATCH][SRU][Xenial] Fix suspend-to-idle power consumption issue

[AceLan Kao]

BugLink: http://bugs.launchpad.net/bugs/1693393

[Impact] 
The power consumption under suspend-to-idle(s2idle) are
   8Watt under 4.4 kernel
   4Watt under 4.8 kernel
   2Watt under 4.11 kernel

There are essential patches in 4.8 and 4.11 kernels, they are
In 4.8
   9d26d3a PCI: Put PCIe ports into D3 during suspend
In 4.11
   8d2c453 platform/x86: dell-laptop: Add Latitude 7480 and others to the DMI whitelist

We just have the SRU patch from 4.11(8d2c453) in our proposed kernel,
so we only need the one in 4.8 kernel(9d26d3a).

[Test]
Using power supply to measure the power consumption, after applied
the 2 patches, the power consumption under s2idle reduce to less than 2Watt.

[Misc]
Sorry to submit again, I forgot to add "cherry picked from" in the patch in
previous submittion.
I know the changes are a little to big for SRU, but it affects 4 Watt power
consumption. And Dell may start to ship their products only with suspend-to-idle
later this year. So, this commit is critical for us, and I can do more
difference testings to make you feel confortable.

Mika Westerberg (1):
  PCI: Put PCIe ports into D3 during suspend

 Documentation/kernel-parameters.txt |   4 +
 drivers/pci/bus.c                   |   1 +
 drivers/pci/pci-driver.c            |   5 +-
 drivers/pci/pci-sysfs.c             |   5 ++
 drivers/pci/pci.c                   | 175 ++++++++++++++++++++++++++++++++++++
 drivers/pci/pci.h                   |  11 +++
 drivers/pci/remove.c                |   2 +
 drivers/usb/host/xhci-pci.c         |   2 +-
 include/linux/pci.h                 |   3 +
 9 files changed, 203 insertions(+), 5 deletions(-)

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2.7.4