dt-bindings: arm-smmu: Document smmu-500 binding for SM6125

Document smmu-500 compatibility with the SM6125 SoC.

Signed-off-by: Martin Botka <martin.botka@somainline.org>
[Marijn: Move compatible to the new, generic, qcom,smmu-500 list]
Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221222193254.126925-2-marijn.suijten@somainline.org


Signed-off-by: Will Deacon <will@kernel.org>