[PATCH] driver model wakeup flags

This is a refresh of an earlier patch to add "wakeup" support to the
PM core model.  This provides per-device bus-neutral control of the
use of wakeup events.

  * "struct device_pm_info" has two bits that are initialized as
    part of setting up the enclosing struct device:
      - "can_wakeup", reflecting hardware capabilities
      - "may_wakeup", the policy setting (when CONFIG_PM)

  * There's a writeable sysfs "wakeup" file, with one of two values:
      - "enabled", when the policy is to allow wakeup
      - "disabled", when the policy is not to allow it
      - "" if the device can't currently issue wakeups

By default, wakeup is enabled on all devices that support it.  If its
driver doesn't support it ... treat it as a bug.  :)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>