OSV-2020-792 Use-of-uninitialized-value in ihevc_inter_pred_chroma_copy_ssse3

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=23197 Crash type: Use-of-uninitialized-value Crash state: ihevcinterpredchromacopyssse3 ihevcdinterpredctb ihevcdprocess...