drm/msm/dp: Add eDP support via aux_bus

This patch adds support for generic eDP sink through aux_bus. The eDP/DP
controller driver should support aux transactions originating from the
panel-edp driver and hence should be initialized and ready.

The panel bridge supporting the panel should be ready before the bridge
connector is initialized. The generic panel probe needs the controller
resources to be enabled to support the aux transactions originating from
the panel probe.

Signed-off-by: Sankeerth Billakanti <quic_sbillaka@quicinc.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/483307/
Link: https://lore.kernel.org/r/1650887072-16652-2-git-send-email-quic_sbillaka@quicinc.com


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