ARM: dts: msm: enable dynamic fps for SDM670

Enabling dynamic fps for nt35597 dsc and nt35597 dual dsi
video panels on sdm670. The feature helps to reduce fps
when static screen leading to power saving.

Change-Id: I4fe16fecf3ad6832648d7a25d061bdbd26af2675
Signed-off-by: Raviteja Tamatam <travitej@codeaurora.org>