ARM: dts: msm: Add regulators for PM660

Add smpa1, smpa2, smpa3, ldoa16 and ldoa18 regulators for PM660.
Also add "qcom,hpm-min-load" DT property for all the regulators.

Change-Id: I6e4eeca92f80838c22ab22934b576fc834d47034
Signed-off-by: Umang Chheda <uchheda@codeaurora.org>