Mismatch of the expected and provided function argument size in MasaFileWriter_open

Found in #887 (closed)

The function MasaFileWrite_open determines the output filename with the call

char filePath[FILENAME_MAX - 12];
getExtMasaMetadataFileName( outputWavFilename, &filePath );

while the function is defined as

static void getExtMasaMetadataFileName(
    const char *outputWavFilename,                                  /* i  : name of the output audio file         */
    char metadata_filename[IVAS_MAX_NUM_OBJECTS][FILENAME_MAX - 12] /* o  : name of the output masa metadata file */
)

Internally, the function uses metadata_filename[0], so no over-indexing takes place.