arm64: dts: qcom: sc7180: Add "dp_hot_plug_det" pinconf for trogdor

We have an external pull on this line, so disable the internal pull.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20210106152537.1.Ib4b5b0e88fdc825c0e2662bab982dda8af2297b2@changeid
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>