Import ACPI smart battery support. Newer systems (Acer, mostly) do not
support the CM-battery interface. Smart batteries can eventually be
supported without ACPI via a separate SMBus interface. The ACPI interface
uses the embedded controller for reading/writing to the SMBus, and normal
ASL definitions for locating the battery controller (since SMBus can't be
enumerated.) Also import definitions for the smart battery interface.

This was written by Hans Petter Selasky with minor cleanups from myself.

Submitted by: Hans Petter Selasky <hselasky / c2i.net>