msm: kgsl: Do not register additional IOMMU faults

When an IOMMU fault occurs the fault is cleared in a
queued work item. Until the queued item runs the system
will report the same fault over and over again. Ignore
these faults until the original fault is cleared in the
queued work item.

Change-Id: I96a63ab8f568a874f25da0c56d1e3d8cf7e73e6c
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>