iommu: add self-consistency tests to ARM LPAE IO page table allocator

This patch adds a series of basic self-consistency tests to the ARM LPAE
IO page table allocator that exercise corner cases in map/unmap, as well
as testing all valid configurations of pagesize, ias and stage.

Change-Id: I703df977b7e5914e0ccf9aaca2174cf5956dd604
Signed-off-by: Will Deacon <will.deacon@arm.com>
Git-commit: fe4b991dcd84e0104cf2e29223a819335ed048a7
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


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