iommu: iommu-debug: Remove arm_iommu_create_mapping

Since this API is being deprecated, replace it with equivalent
functionality. Also clean up any references to "archdata", and
perform checks whether the test device has a domain while holding
a mutex.

Change-Id: If6fcfec95d59628ac5162553db6383dd465dd5b2
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>