ACPI power management fix for 3.18-rc6

This is just a one-liner fixing a regression introduced in 3.13 that
 broke system suspend on some Chromebooks.
 
 On those machines there are ACPI device objects for some I2C devices
 that can wake up the system from sleep states, but that is done via
 a platform-specific mechanism and the ACPI objects don't contain any
 wakeup-related information.  When we started to use ACPI power
 management with those devices (which happened during the 3.13 cycle),
 their configuration confused the ACPI PM layer that returned error
 codes from suspend callbacks for them causing system suspend to fail.
 
 However, the ACPI PM layer can safely ignore the wakeup setting from
 a device driver if the ACPI object corresponding to the device in
 question doesn't contain wakeup information in which case the driver
 itself is responsible for setting up the device for system wakeup.
 
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Merge tag 'pm+acpi-3.18-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI power management fix from Rafael Wysocki:
 "This is just a one-liner fixing a regression introduced in 3.13 that
  broke system suspend on some Chromebooks.

  On those machines there are ACPI device objects for some I2C devices
  that can wake up the system from sleep states, but that is done via a
  platform-specific mechanism and the ACPI objects don't contain any
  wakeup-related information.  When we started to use ACPI power
  management with those devices (which happened during the 3.13 cycle),
  their configuration confused the ACPI PM layer that returned error
  codes from suspend callbacks for them causing system suspend to fail.

  However, the ACPI PM layer can safely ignore the wakeup setting from a
  device driver if the ACPI object corresponding to the device in
  question doesn't contain wakeup information in which case the driver
  itself is responsible for setting up the device for system wakeup"

* tag 'pm+acpi-3.18-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / PM: Ignore wakeup setting if the ACPI companion can't wake up

drivers/acpi/device_pm.c

@@ -878,7 +878,7 @@ int acpi_dev_suspend_late(struct device *dev)
 		return 0;
 
 	target_state = acpi_target_system_state();
-	wakeup = device_may_wakeup(dev);
+	wakeup = device_may_wakeup(dev) && acpi_device_can_wakeup(adev);
 	error = acpi_device_wakeup(adev, target_state, wakeup);
 	if (wakeup && error)
 		return error;