regulator: cpr3-regulator: ensure monotonicity of CPR floor voltages

Modify the cpr3-regulator driver so that it guarantees that CPR
floor voltages increase monotonically from lower to higher
corners.  This is necessary to ensure stable operation when the
vdd-supply voltage drops to the floor voltage of a corner after
all CPR sensors of a given CPR hardware thread are bypassed
during HMSS cluster power collapse.

Change-Id: Ib24836552cef95418b8fa3468e92b8a5bb18d592
Signed-off-by: David Collins <collinsd@codeaurora.org>