gauguin-q-oss tree does not compile

From a basic setup using kernel e601e14 and device tree 726054c:

arch/arm64/boot/dts/vendor/qcom/gauguin-sm6350-overlay.dtbo: ERROR (duplicate_property_names): /fragment@46/__overlay__:qcom,mdss-dsi-bl-max-level: Duplicate property name
arch/arm64/boot/dts/vendor/qcom/gauguin-sm6350-overlay.dtbo: ERROR (duplicate_property_names): /fragment@47/__overlay__:qcom,mdss-dsi-bl-max-level: Duplicate property name
arch/arm64/boot/dts/vendor/qcom/gauguin-sm6350-overlay.dtbo: ERROR (duplicate_property_names): /fragment@48/__overlay__:qcom,mdss-dsi-bl-max-level: Duplicate property name
arch/arm64/boot/dts/vendor/qcom/gauguin-sm6350-overlay.dtbo: ERROR (duplicate_property_names): /fragment@49/__overlay__:qcom,mdss-dsi-bl-max-level: Duplicate property name
arch/arm64/boot/dts/vendor/qcom/gauguin-sm6350-overlay.dtbo: ERROR (duplicate_property_names): /fragment@50/__overlay__:qcom,mdss-dsi-bl-max-level: Duplicate property name
arch/arm64/boot/dts/vendor/qcom/gauguin-sm6350-overlay.dtbo: ERROR (duplicate_property_names): /fragment@51/__overlay__:qcom,mdss-dsi-bl-max-level: Duplicate property name
ERROR: Input tree has errors, aborting (use -f to force output)
make[4]: *** [scripts/Makefile.dtbo:25: arch/arm64/boot/dts/vendor/qcom/gauguin-sm6350-overlay.dtbo] Error 2
make[3]: *** [../scripts/Makefile.build:643: arch/arm64/boot/dts/vendor/qcom] Error 2
make[2]: *** [../scripts/Makefile.build:643: arch/arm64/boot/dts/vendor] Error 2
make[1]: *** [arch/arm64/Makefile:159: dtbs] Error 2
make: *** [Makefile:146: sub-make] Error 2

I've made a potential patch over at https://github.com/FloatingGhost/device_tree_xiaomi_gauguin which fixes compilation and allows a device to boot based on the dtb image, but i'm not well-versed enough in how the kernel works to know if this is the right way to go about it

Start with the gauguin-sm6350-overlay device-tree build and the duplicate qcom,mdss-dsi-bl-max-level errors reported for fragments 46 through 51. Review the proposed patch in device_tree_xiaomi_gauguin, then rebuild the dtbs target; the work is done when the overlay compiles without duplicate-property errors and the resulting device-tree image remains bootable.