arm64: dts: qcom: sc7180: Add DisplayPort HPD pin dt node

This node defines alternate DP HPD functionality of GPIO.

Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Tanmay Shah <tanmay@codeaurora.org>
Link: https://lore.kernel.org/r/20200818033657.16074-1-tanmay@codeaurora.org


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>