arm64: dts: qcom: sc7180: rename labels for DSI nodes

Currently in board files MDSS and DSI nodes stay apart, because labels
for DSI nodes do not have the mdss_ prefix. It was found that grouping
all display-related notes is more useful.

To keep all display-related nodes close in the board files, change DSI
node labels from dsi_* to mdss_dsi_*.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230531011623.3808538-8-dmitry.baryshkov@linaro.org