hammerhead: add slim govenor

thanks a ton to flar2 where this govenor is based on. Small modifications done
and more will follow in future.

ToDo: we need to set the govenor as default as well other small modifications
to ramdisk

Change-Id: Ia7ea6714715103a24e0bbbddcff9e1d0e0771380
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>

Conflicts:
	arch/arm/configs/bricked_defconfig
	drivers/cpufreq/Makefile
	drivers/cpufreq/cpufreq_slim.c