iommu/arm-smmu: use VA_BITS to determine arm64 virtual address space
iommu/arm-smmu: use VA_BITS to determine arm64 virtual address space

With the introduction of the VA_BITS definition for arm64, make use of
it in the driver, allowing up to 42-bits of VA space when configured
with 64k pages.

Signed-off-by: Will Deacon <b913f13ef92ac157955c954ccaaff7be065faba4@arm.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs