iommu/arm-smmu: fix calculation of TCR.T0SZ

T0SZ controls the input address range for TTBR0, so use the input
address range rather than the output address range for the calculation.
For stage-2, this means using the output size of stage-1.

Change-Id: Ia1b0d3c6241cabf8eb1d72111b76ae0ca5f8d6c0
Signed-off-by: Will Deacon <will.deacon@arm.com>
Git-commit: a65217a4bcdb654e04fcc42b302d8a15708e14ce
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git


Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>