avcodec/aacdec_template: Avoid undefined negation in imdct_and_windowing_eld()
Fixes: negation of -2147483648 cannot be represented in type 'INTFLOAT' (aka 'int'); cast to an unsigned type to negate this value to itself Fixes: 29057/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AAC_FIXED_fuzzer-5642758933053440 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>