avcodec/mpegaudiodec_template: Fix runtime error: signed integer overflow: 2053224902 + 2053224902 cannot be represented in type 'int'

Fixes: 696/clusterfuzz-testcase-5853632270434304

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/mpegaudiodec_template.c

@@ -457,7 +457,7 @@ static av_cold int decode_init(AVCodecContext * avctx)
 
 /* 12 points IMDCT. We compute it "by hand" by factorizing obvious
    cases. */
-static void imdct12(INTFLOAT *out, INTFLOAT *in)
+static void imdct12(INTFLOAT *out, SUINTFLOAT *in)
 {
     SUINTFLOAT in0, in1, in2, in3, in4, in5, t1, t2;