iommu: arm-smmu: Update safe errata sequence

Under certain circumstatnces, TLB invalidate operations were timing
out with the previous sequence. Make an scm call to disable the SAFE
errata after the first timeout.

Change-Id: Id2ca71bb3f308396eded69ebf8fc35fe80c443da
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>