framing.c: overflow on left shift

There's a regression since commit bc82844d: framing.c:239:19: runtime error: left shift of 211 by 24 places cannot be represented in type 'int'

I found this while generating the corpus for speex with oss-fuzz:

git clone git@github.com:tmatth/oss-fuzz.git
cd oss-fuzz
python infra/helper.py build_image speex
python infra/helper.py build_fuzzers --sanitizer undefined speex