arm64: dts: qcom: msm8996: rename labels for HDMI nodes

In board files MDSS and HDMI nodes do not come next to each other,
because labels for HDMI nodes do not have the common mdss_ prefix.

Follow the DSI example and enable such grouping by changing the prefix
for HDMI labels to mdss_hdmi_*.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20230615083422.350297-3-dmitry.baryshkov@linaro.org


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