clk: msm: clock-cpu: Add support for hardware boost and vmin

The performance boost enhances the voltage and over clocks the CPU
subsystem when less number of cores are online. The limit on how many
cores can run at this higher voltage/frequency corner can be dynamically
programmable by software.

The CPR sensors give the recommendation of voltage based on the frequency
at which the cores are running. But it is ignorant of the number of online
cores and gives feedback assuming all the cores are online. But if less
number of cores are online, we can further reduce the voltage to save
power. The vmin reduction FSM does that precisely.

Change-Id: I305c916f0f7a5fc8deec07caee7e290344d70825
Signed-off-by: Taniya Das <tdas@codeaurora.org>