utils: replace snprintf calls with mxf_snprintf
utils: replace snprintf calls with mxf_snprintf

stuarthicks/libmxf,stuarthicks/libmxf,Limecraft/ebu-libmxf,Limecraft/ebu-libmxf,stuarthicks/libmxf,Limecraft/ebu-libmxf,stuarthicks/libmxf