OSV-2022-696 Use-of-uninitialized-value in mix_add_scale_stride

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=49921 Crash type: Use-of-uninitialized-value Crash state: mixaddscalestride crasmixaddscalestride crasaudioareacopy...