ARM: dts: qcom: Enable RPM regulators on apq8074 dragonboard

Add the appropriate min/max voltages for the regulators on the
apq8074 dragonboard so that they can be used by clients properly.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>