ARM: dts: msm: Add vdd restriction support for MSM8939/MSM8936

Enable the vdd restriction feature for VDD_DIG and VDD_APPS when
low temperature condition happens on MSM8939/MSM8936. Specify the
low temperature thresholds, add the voltage rail and cpu frequency
information. Voltage floor will be set when threshold is crossed,
voltage floor will be cleared when threshold hysteresis is crossed.

Change-Id: I283a0b69a5b8df1fc1d91e7f0b386426ec9fb61c
Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>