Move more knowledge of sense data format out of hw/scsi/scsi-bus.c
for reusability.
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>