ARM: dts: msm: use CPR virtual corners for APC0 and APC1 on msm8994

Switch the APC0 and APC1 cpr-regulator devices from using fuse
voltage corners to using virtual voltage corners.  Each virtual
corner is mapped to a single cluster clock frequency.  This
allows for the CPR target quotient to be scaled down for lower
frequencies that are assigned to a given fuse voltage corner.
Reducing the target quotient results in the CPR controllers
recommending lower voltages.  This saves power when operating
at frequencies other than the high one mapped to a given fuse
corner.

Change-Id: I6a45780bb72b91daeaa6cd4bc19906197e1a540a
Signed-off-by: Ke Liu <keliu@codeaurora.org>
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
Signed-off-by: David Collins <collinsd@codeaurora.org>