msm: cpr-regulator: add CPR driver code

Add RB-CPR (Rapid Bridge core power reduction) code in cpr-regulator
driver, which reads both eFuse and device tree for configuration
parameters and programs CPR registers accordingly. The driver
will scale the voltage up or down based on the CPR hardware's
suggestion. It also changes CPR mode when Apps cpu clock changes
corner voltage. If any part doesn't have efuse at all, assume it's
a slow part and do not use CPR.

Change-Id: Ia3dc5a6ec013647f2a21577c0fe0f2b30a93cd73
Signed-off-by: Willie Ruan <wruan@codeaurora.org>