cdrom_id: Try reading the medium if all MMC commands fail

Reportedly, some "when I'm grown up I want to be a CD drive" fake USB CD sticks
like the IronKey neither support the SCSI "GET CONFIGURATION" nor the older
(pre-MMC2) "READ DISC INFORMATION" command. In that case, check if we can read
data from the drive, and assume that we have a CD-ROM medium if it succeeds.