iommu/arm-smmu-qcom: Initialize SCTLR of the bypass context

On SM8150 it's occasionally observed that the boot hangs in between the
writing of SMEs and context banks in arm_smmu_device_reset().

The problem seems to coincide with a display refresh happening after
updating the stream mapping, but before clearing - and there by
disabling translation - the context bank picked to emulate translation
bypass.

Resolve this by explicitly disabling the bypass context already in
cfg_probe.

Fixes: f9081b8f

 ("iommu/arm-smmu-qcom: Implement S2CR quirk")
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210106005038.4152731-1-bjorn.andersson@linaro.org
Signed-off-by: Will Deacon <will@kernel.org>