avcodec/cbs_apv: use av_unreachable instead of av_assert0(0) at the end of a non-void function

Fixes compilation with gcc-tsan and --disable-optimizations

Signed-off-by: James Almer <jamrial@gmail.com>

libavcodec/cbs_apv.c

@@ -33,7 +33,7 @@ static int cbs_apv_get_num_comp(const APVRawFrameHeader *fh)
     case APV_CHROMA_FORMAT_4444:
         return 4;
     default:
-        av_assert0(0 && "Invalid chroma_format_idc");
+        av_unreachable("Invalid chroma_format_idc");
     }
 }