ARM: dts: msm: Enable system PM to high power saving mode on SDM710

During system suspend, power-down the device and turn-off the link.
This will ensure higher power-savings.

Change-Id: I68c4c54012b0a7c9343339d8d85c5ac7806021a1
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>