Fix checksums for GSM data.
Fix checksums for GSM data.

dsanders11/rtpproxy,hongbinz/rtpproxy,jevonearth/rtpproxy,sippy/rtpproxy,synety-jdebp/rtpproxy,Vocalocity/rtpproxy-pre,jevonearth/rtpproxy,dsanders11/rtpproxy,synety-jdebp/rtpproxy,Vocalocity/rtpproxy-pre,Vocalocity/rtpproxy-pre,sippy/rtpproxy,hongbinz/rtpproxy,Vocalocity/rtpproxy-pre,hongbinz/rtpproxy,jevonearth/rtpproxy,synety-jdebp/rtpproxy,dsanders11/rtpproxy,hongbinz/rtpproxy,synety-jdebp/rtpproxy,jevonearth/rtpproxy,sippy/rtpproxy