msm: acpuclock-8974: Update vdd_dig votes to use new voltage corners

New voltage corner enums have been introduced in the RPM regulator
driver for msm8974's vdd_dig rail. Update acpuclock accordingly.

Change-Id: Id4d316b25cdc61d7a0ee330f6423f242881fca0b
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>