iommu/arm-smmu: Fix the values of ARM64_TCR_{I,O}RGN0_SHIFT

The arm64 CPU architecture defines TCR[8:11] as holding the inner and
outer memory attributes for TTBR0.

This patch fixes the ARM SMMUv3 driver to pack these bits into the
context descriptor, rather than picking up the TTBR1 attributes as it
currently does.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>