defconfig: arm64: msm: enable cpr-regulator driver

Enable the cpr-regulator driver so that it may be used on arm64
targets.  It will initially be used by MSM8916 boards in order
to control the VDD_APC power rail which supplies the application
processor cores.

Change-Id: I96422821c88954d48ad93862137854cf18c1572a
Signed-off-by: David Collins <collinsd@codeaurora.org>