arm/dt: msm9625: Add regulator device constraints and labels

Utilize the QPNP regulator devices for MSM9625 targets in place of
the RPM regulator devices so that regulators may be correctly
controlled before RPM support is in place.  Add voltage
constraints and supply chain mapping via a new target specific
device tree include file.

Change-Id: I6ca4524d2de0e98ff93a3ded106c97632e2c356d
Signed-off-by: David Collins <collinsd@codeaurora.org>