msm: cpr-regulator: add support for virtual corner based quotient scaling

The current cpr-regulator driver implementation uses the same CPR target
quotient, which is read from a fuse, for all CPU frequencies handled by a
given voltage corner. This results in unnecessary additional power
consumption when operating the CPU at one of the lower frequencies handled
by one voltage corner. Hence change the driver to adjust the CPR quotient
value according to the virtual corner corresponding to the CPU frequency.

CRs-Fixed: 583719
Change-Id: Ia95688b8c6e88d14da1ac9311d73148802105d0a
Signed-off-by: Ke Liu <keliu@codeaurora.org>