hwc2: Workaround use after free by surfaceflinger

Works around bug 30281222 by dup'ing the ion fd we get in
SetLayerBuffer so that it isn't closed during the commit cycle.

Bug: 31016569
Bug: 30281222
CRs-Fixed: 1061972
Change-Id: I98c473ad24bbc0e1f999d41b218615c8f9f7cd10
2 files changed