msm: cpr-regulator: add support for increasing cpr quotient value

Add support for the specification of a fixed offset value to be added to
the CPR target quotient for each voltage corner. This can be used to
increase the static voltage margin of a supply managed by a CPR controller.

CRs-fixed: 605127
Change-Id: I0e8f71b35b8ea3bb1724d6e01944015d5fbcb045
Signed-off-by: Ke Liu <keliu@codeaurora.org>