iommu/iommu-debug: Pass a flags value to iommu_trigger_fault

iommu_trigger_fault now accepts a flags argument which can be handled by
the individual IOMMU drivers.  Take the value written to the debugfs
file by the user and pass it as the flags value.

Change-Id: I803e6585aea35fbb0f6e03e4279587b36a7bad92
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>