avcodec/aacdec_template: Fix fixed point scale in decode_cce()

Fixes: runtime error: shift exponent 1073741824 is too large for 32-bit type 'int'
Fixes: 1654/clusterfuzz-testcase-minimized-5151903795118080

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