avcodec/alac: Fix multiple integer overflows in lpc_prediction()

avcodec/alac: Fix multiple integer overflows in lpc_prediction()

Fixes: signed integer overflow: 2088795537 + 2147254401 cannot be represented in type 'int'
Fixes: signed integer overflow: -1500363496 + -1295351808 cannot be represented in type 'int'
Fixes: signed integer overflow: -79560 * 32640 cannot be represented in type 'int'
Fixes: signed integer overflow: 2088910005 + 2088796058 cannot be represented in type 'int'
Fixes: signed integer overflow: -117258064 - 2088725225 cannot be represented in type 'int'
Fixes: signed integer overflow: 2088725225 - -117258064 cannot be represented in type 'int'
Fixes: 15739/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ALAC_fuzzer-5630664122040320
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>