msm: mdss: add dynamic clk status check to pipe idle verification

Dynamic clk status of pipe can indicate if that pipe is active or not.
This status in conjunction VBIF halt status of pipe describes the idle
state of the pipe. Add support to parse necessary offsets from DT and
use them to find idle state of the pipe.

Change-Id: I83c6f323d48a85bfc08ff7bcee47f7c3038ea7e1
Signed-off-by: Ujwal Patel <ujwalp@codeaurora.org>

Conflicts:
	arch/arm/boot/dts/msm8974-mdss.dtsi