qcom: clock-cpu-8994: Populate absolute voltages in CPU-device OPP tables

Previously, the MSM8994 CPU clock driver populated the
two CPR regulator devices (one per CPU power rail) with
OPP tables containing frequency to corner mappings. The
CPR regulator driver will now populate its own devices
with corner to voltage mappings. If those OPP tables are
present, populate the CPU devices with frequency to voltage
mappings.

Change-Id: Iebbb0a03040686566dd2c65ecb8248869e1359f5
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>