iommu/arm-smmu: support buggy implementations with secure cfg accesses

In such a case we have to use secure aliases of some non-secure
registers.

This handling is switched on by DT property
"calxeda,smmu-secure-config-access" for an SMMU node.

Change-Id: I0d109375c4a83cd414d6fcba0200ef1e201ee44d
Signed-off-by: Andreas Herrmann <andreas.herrmann@calxeda.com>
[will: merged with driver option handling patch]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Git-commit: 3a5df8ff35a28bfc0a3662a5906af2c98d4807d8
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


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