drm/bridge: ti-sn65dsi86: Properly undo autosuspend

The PM Runtime docs say:
  Drivers in ->remove() callback should undo the runtime PM changes done
  in ->probe(). Usually this means calling pm_runtime_disable(),
  pm_runtime_dont_use_autosuspend() etc.

We weren't doing that for autosuspend. Let's do it.

Fixes: 9bede631 ("drm/bridge: ti-sn65dsi86: Use pm_runtime autosuspend")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220222141838.1.If784ba19e875e8ded4ec4931601ce6d255845245@changeid