Currently QEMU passes the qdev device id to the guest in an ASCII-string
designator in page 0x83.  While this is fine, it does not match what
real hardware does; usually the ASCII-string designator there hosts
another copy of the serial number (there can be other designators,
for example with a world-wide name).  Do the same for QEMU SCSI
disks.

ATAPI does not support VPD pages, so it does not matter there.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>