arm64: dts: qcom: sm8250: Enable per-process page tables.

This is an SMMU for the adreno gpu, and adding this compatible lets
the driver use per-fd page tables, which are required for security
between GPU clients.

Signed-off-by: Emma Anholt <emma@anholt.net>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
[bjorn: Move arm,smmu-500 last, per Dmitry's request]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220614230136.3726047-2-emma@anholt.net