iris: Don't use STREAMING_LOAD without SSE4.2
What does this MR do and why?
iris: Don't use STREAMING_LOAD without SSE4.2
isl will assert out otherwise. Hit this with intel_stub_gpu on arm64, but it is a legitimate bug since someone might plug a DG2 card into a workstation-grade arm64 or ppc64 supporting PCIe (it exists).
Signed-off-by: Alyssa Rosenzweig alyssa@rosenzweig.io