arm64: dts: qcom: sm8150-hdk: enable HDMI output

Add DSI outputs and link them to the onboard Lontium LT9611 DSI-to-HDMI
bridge, enabling HDMI output on this board. While adding the display
resources, also drop the headless ("amd,imageon") compat string from the
GPU node, since the board now has output.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20231215174152.315403-3-dmitry.baryshkov@linaro.org


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