arm64: dts: qcom: Unify the sc7180-trogdor panel nodes

Let's avoid a bit of duplication by pushing this up to the trogdor.dtsi
file.

Suggested-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20210301133318.v2.4.I1483fac4c5ae4b2d7660290ff85d69945292618f@changeid


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