regulator: cpr-regulator: Add virtual-corner voltage/quotient adjustment

Add support to adjust the target quotient and init-voltage per virtual
corner. The adjustment values are specified via DT properties.
This allows finer granularity for quotient/voltage adjustments.

CRs-Fixed: 762377
Change-Id: I3deffb070a0156acf9ceaa138357ae208a86df59
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>