ARM: dts: msm: add a VDD_APC cpr-regulator device for msm8916

Replace the regulator-apc-corner qcom,stub-regulator device node with a
qcom,cpr-regulator device node. This allows for the PM8916 SMPS 2
regulator voltage to set based upon voltage corners requested from the
cpr-regulator device as well as CPR hardware recommendations.

Change-Id: Ibda3086b79486bb476e17e087c9fd0f4af361783
Signed-off-by: Wu Fenglin <fenglinw@codeaurora.org>