SCSI CD-ROM fixes of the day.

1.Re-implemented in the best way possible the muted part of the Toshiba/NEC Play Audio commands and related, per spec.
2. Forgot to add a check to a Sony Vendor Data Out command  when the len is 0 it should become a Status command, fixes emulator crashes when len is 0 using some CD software.

src/include/86box/cdrom.h

@@ -244,6 +244,7 @@ typedef struct cdrom {
     int prev_host_drive;
     int cd_buflen;
     int audio_op;
+    int audio_muted_soft;
     int sony_msf;
 
     const cdrom_ops_t *ops;