ACPI / PM: Expose lists of device power resources to user space

Since ACPI power resources are going to be used more extensively on
new hardware platforms, it is necessary to allow user space (powertop
in particular) to look at the lists of power resources corresponding
to different power states of devices for diagnostics and control
purposes.

For this reason, for each power state of an ACPI device node using
power resources create a special attribute group under the device
node's directory in sysfs containing links to sysfs directories
representing the power resources in that list.  The names of the
new attribute groups are "power_resources_<state>", where <state>
is the state name i.e. "D0", "D1", "D2", or "D3hot".

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'acpi-cleanup-next' into bleeding-edge

* acpi-cleanup-next:
  ACPI: Drop device start operation that is not used
  ACPI: Remove useless type argument of driver .remove() operation
Merge branch 'acpi-pm-next' into bleeding-edge

* acpi-pm-next:
  ACPI / PM: Expose lists of device power resources to user space
  sysfs: Functions for adding/removing symlinks to/from attribute groups
  ACPI / PM: Expose current status of ACPI power resources
  ACPI / PM: Expose power states of ACPI devices to user space