cm_sbs_sem is being downed (via acpi_ac_init->acpi_lock_ac_dir) before it is
initialised, with grave results.

- Make it a mutex

- Initialise it

- Make it static

- Clean other stuff up.

Thanks to Paul Drynoff <pauldrynoff@gmail.com> for reporting and testing.

Cc: Rich Townsend <rhdt@bartol.udel.edu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLen Brown <len.brown@intel.com>

a few invocations appeared due to the SBS and other patches.
Signed-off-by: NLen Brown <len.brown@intel.com>

Most batteries today are ACPI "Control Method" batteries,
but some models ship with the older "Smart Battery"
that requires this code.

Rich Townsend and Bruno Ducrot were the original authors.
Vladimir Lebedev updated to run on latest kernel.

http://bugzilla.kernel.org/show_bug.cgi?id=3734Signed-off-by: NLen Brown <len.brown@intel.com>