drm/msm/a6xx: don't set IO_PGTABLE_QUIRK_ARM_OUTER_WBWA with coherent SMMU

If the Adreno SMMU is dma-coherent, allocation will fail unless we
disable IO_PGTABLE_QUIRK_ARM_OUTER_WBWA. Skip setting this quirk for the
coherent SMMUs (like we have on sm8350 platform).

Fixes: 54af0ceb ("arm64: dts: qcom: sm8350: add GPU, GMU, GPU CC and SMMU nodes")
Reported-by: David Heidelberg <david@ixit.cz>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tested-by: David Heidelberg <david@ixit.cz>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Tested-by: Konrad Dybcio <konrad.dybcio@linaro.org> # SM8450 HDK
Patchwork: https://patchwork.freedesktop.org/patch/531562/


Signed-off-by: Rob Clark <robdclark@chromium.org>