iommu : arm-smmu : Fetch right SID in qsmmuv500_iova_to_phys_hard

Introduce a new field is_debug_domain in iommu_domain
structure to distinguish a domain which belongs to a
test device from a domain which belongs to an actual device.
Pick the SID from the iommu domain's fwspec, if is_debug_domain
is set to true i.e during trigger-fault or ECATS.
Pick the SID from the corresponding frsynra register if
is_debug_domain is set to false.

Change-Id: I7c6614afe3afc82906c2b8cd446d3b55385a66d1
Signed-off-by: Swathi Sridhar <swatsrid@codeaurora.org>