iommu/arm-smmu-qcom: Add stall support

iommu/arm-smmu-qcom: Add stall support

Add, via the adreno-smmu-priv interface, a way for the GPU to request
the SMMU to stall translation on faults, and then later resume the
translation, either retrying or terminating the current translation.

This will be used on the GPU side to "freeze" the GPU while we snapshot
useful state for devcoredump.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Acked-by: Jordan Crouse <jordan@cosmicpenguin.net>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210610214431.539029-5-robdclark@gmail.com
Signed-off-by: Rob Clark <robdclark@chromium.org>