iommu/arm-smmu: Simplify VMID and ASID allocation

We only use ASIDs and VMIDs to identify individual stage-1 and stage-2
context-banks respectively, so rather than allocate these separately
from the context-banks, just calculate them based on the context bank
index.

Note that VMIDs are offset by 1, since VMID 0 is reserved for stage-1.
This doesn't cause us any issues with the numberspaces, since the
maximum number of context banks is half the minimum number of VMIDs.

Change-Id: I6c85fd09ae0beac5ff4b7716acdca0c5ebcbe2f0
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>
Git-commit: ecfadb6e5b49a0a56df2038bf39f1fcd652788b9
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


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