'ivasmasaFormatDescriptor' defined at three different files

ivasmasaFormatDescriptor[8] is defined in three different files. It would be better to define it in one common place.

..\lib_dec\ivas_masa_dec.c(1838):       const uint8_t ivasmasaFormatDescriptor[8] = { 0x49, 0x56, 0x41, 0x53, 0x4D, 0x41, 0x53, 0x41 }; /* "IVASMASA" */
..\lib_rend\ivas_mcmasa_ana.c(1072):    const uint8_t ivasmasaFormatDescriptor[8] = { 0x49, 0x56, 0x41, 0x53, 0x4D, 0x41, 0x53, 0x41 }; /* "IVASMASA" */
..\lib_util\masa_file_reader.c(114):    const uint8_t ivasmasaFormatDescriptor[8] = { 0x49, 0x56, 0x41, 0x53, 0x4D, 0x41, 0x53, 0x41 }; /* "IVASMASA" */