drm/panel: atna33xc20: Fix unbalanced regulator in the case HPD doesn't assert

When the atna33xc20 driver was first written the resume code never
returned an error. If there was a problem waiting for HPD it just
printed a warning and moved on. This changed in response to review
feedback [1] on a future patch but I accidentally didn't account for
rolling back the regulator enable in the error cases. Do so now.

[1] https://lore.kernel.org/all/5f3cf3a6-1cc2-63e4-f76b-4ee686764705@linaro.org/



Fixes: 3b5765df ("drm/panel: atna33xc20: Take advantage of wait_hpd_asserted() in struct drm_dp_aux")
Acked-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240313-homestarpanel-regulator-v1-1-b8e3a336da12@chromium.org