drm/panel: himax-hx8394: Drop shutdown logic

drm/panel: himax-hx8394: Drop shutdown logic

The driver shutdown is duplicate as it calls drm_unprepare and
drm_disable which are called anyway when associated drivers are
shutdown/removed.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20231204185719.569021-3-macroalpha82@gmail.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231204185719.569021-3-macroalpha82@gmail.com