ARM: dts: msm: Enable iommu_unmap_fast path for trinket GPU SMMU

GPU SMMU on trinket supports TLB invalidation across power collapse.
Enable iommu_unmap_fast path to skip redundant TLB invalidation
when SMMU regulator is in OFF state.

Add qcom,unamp_fast entry to exercise iommu_unmap_fast path.

Change-Id: I079820b703fcbd9cce8c5464ff275932d68d4667
Signed-off-by: Rajesh Kemisetti <rajeshk@codeaurora.org>