drm/msm/dsi: switch to DRM_PANEL_BRIDGE

Currently the DSI driver has two separate paths: one if the next device
in a chain is a bridge and another one if the panel is connected
directly to the DSI host. Simplify the code path by using panel-bridge
driver (already selected in Kconfig) and dropping support for
handling the panel directly.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/493608/
Link: https://lore.kernel.org/r/20220712132258.671263-1-dmitry.baryshkov@linaro.org


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>