drm/panel: himax-hx83102: If prepare fails, disable GPIO before regulators

The enable GPIO should clearly be set low before turning off
regulators. That matches both the inverse order that things were
enabled and also the order in unprepare().

Fixes: 0ef94554 ("drm/panel: himax-hx83102: Break out as separate driver")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240517143643.6.Id0659a80147cf51e0ebb8fe7fee18db86851960d@changeid


Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240517143643.6.Id0659a80147cf51e0ebb8fe7fee18db86851960d@changeid