dt-bindings: arm-smmu: Add compatible for SM6350 SoC

Add the SoC specific compatible for SM6350 implementing
arm,mmu-500.

Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210820202906.229292-1-konrad.dybcio@somainline.org


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