msm: iommu: Support IOMMU page fault reporting

Provide the ability to report IOMMU fault events through
the IOMMU API. The driver will fall back on the previous
behavior of printing the fault information registers if no
domain fault handler is registered, or if the handler
returns -ENOSYS.

Change-Id: I9144e9b4bba117b67c7d81609e986ea716b34882
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>