ARM: dts: msm: Add support for camss throttle clock on SDM660

Camss throttle clock is always on which is consuming power.
To avoid this add support to dynamically enable and disable
clock.

Change-Id: I2eddb414f5c1a22ab42154d28a05e41e64cb5bc9
Signed-off-by: Shilpa Mamidi <shilpam@codeaurora.org>