video: dw_hdmi: Extend the HPD detection

video: dw_hdmi: Extend the HPD detection

HPD detection on some DW HDMI designed SoC's would need to read and
setup the HPD status explicitly.

So, extend the HPD detection code by adding the dw_hdmi_detect_hpd
function and move the default detection code caller there.

The new read and setup hdp will integrate the same function in
later patches.

Signed-off-by: Jagan Teki <jagan@edgeble.ai>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>