drm/bridge: ti-sn65dsi86: Move all the chip-related init to the start

This is just code motion of the probe routine to move all the things
that are for the "whole chip" (instead of the GPIO parts or the
MIPI-to-eDP parts) together at the start of probe. This is in
preparation for breaking the driver into sub-drivers.

Since we're using devm for all of the "whole chip" stuff this is
actually quite easy now.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210423095743.v5.8.Ide8ba40feb2e43bc98a11edbb08d696d62dcd83e@changeid