msm: rpm-9615: Update RPM enums for corner voltages

Update RPM enumeration for 9615 to include the corner voltage enums.
RPM can identify the process differences in SoCs and apply better corner
voltages for power benefit.

Change-Id: I5a55cc4008e1e455911656619b788bb040168fb8
CRs-fixed: 354458
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>
Signed-off-by: David Collins <collinsd@codeaurora.org>