drm/msm/disp/dpu: get timing engine status from intf status register

Recommended way of reading the interface timing gen status is via
status register. Timing gen status register will give a reliable status
of the interface especially during ON/OFF transitions. This support was
added from DPU version 5.0.0.

Signed-off-by: Vinod Polimera <quic_vpolimer@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/524724/
Link: https://lore.kernel.org/r/1677774797-31063-6-git-send-email-quic_vpolimer@quicinc.com


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>