msm: cpr: Add margin and range for step quot

Based on chip characterization data, it is good to add some
margin on top of calculated step quot to help reduce the
number of CPR interrupts. The present value suggested is 3.
Further, if the step quot is outside range, clamp it to the
maximum permitted value.

Change-Id: Ibe161a9b4ea69b78e16cdaa70daa81ae8acc34a0
Signed-off-by: Kaushal Kumar <kaushalk@codeaurora.org>