drm/msm/dsi: don't powerup at modeset time for parade-ps8640

Commit 7d8e9a90 ("drm/msm/dsi: move DSI host powerup to modeset
time") caused sc7180 Chromebooks that use the parade-ps8640 bridge
chip to fail to turn the display back on after it turns off.

Unfortunately, it doesn't look easy to fix the parade-ps8640 driver to
handle the new power sequence. The Linux driver has almost nothing in
it and most of the logic for this bridge chip is in black-box firmware
that the bridge chip uses.

Also unfortunately, reverting the patch will break "tc358762".

The long term solution here is probably Dave Stevenson's series [1]
that would give more flexibility. However, that is likely not a quick
fix.

For the short term, we'll look at the compatible of the next bridge in
the chain and go back to the old way for the Parade PS8640 bridge
chip. If it's found that other bridge chips also need this workaround
then we can add them to the list or consider inverting the
condition. However, the hope is that the framework will not take too
much longer to land and we won't have to add anything other than
ps8640 here.

[1] https://lore.kernel.org/r/cover.1646406653.git.dave.stevenson@raspberrypi.com

Fixes: 7d8e9a90

 ("drm/msm/dsi: move DSI host powerup to modeset time")
Suggested-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Link: https://lore.kernel.org/r/20220513131504.v5.1.Ia196e35ad985059e77b038a41662faae9e26f411@changeid
Signed-off-by: Rob Clark <robdclark@chromium.org>