cpufreq: interactive reaise input_boost_freq again

Signed-off-by: Blechd0se <alex.christ@hotmail.de>
power: battery: implement dedicated workqueue

Instead of using a delay function and create a new kthread
we can just let the scheduler decide when to update our
battery stats.
This should reduce the overhead quite a bit, although no
*real* change in terms of functionwise should be noticeable.

All changes are made generic to support even SMP systems.

Signed-off-by: Blechd0se <alex.christ@hotmail.de>