scsi-disk: small clean up to INQUIRY

Set s->removable, s->qdev.blocksize and s->qdev.type in the callers
of scsi_initfn.

With this in place, s->qdev.type is allowed, and we can just reuse it
as the first byte in VPD data (just like we do in standard INQUIRY data).
Also set s->removable is set consistently and we can use it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>