scsi-disk: removable hard disks support load/eject

Support for the LOEJ bit of the START/STOP UNIT command right now is
limited to CD-ROMs.  This is wrong, since removable hard disks (in the
real world: SD card readers) also support it in pretty much the same way.

Without the LOEJ bit, START/STOP UNIT does nothing for all devices.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

hw/scsi-disk.c

@@ -1248,7 +1248,7 @@ static int scsi_disk_emulate_start_stop(SCSIDiskReq *r)
     bool start = req->cmd.buf[4] & 1;
     bool loej = req->cmd.buf[4] & 2; /* load on start, eject on !start */
 
-    if (s->qdev.type == TYPE_ROM && loej) {
+    if ((s->features & (1 << SCSI_DISK_F_REMOVABLE)) && loej) {
         if (!start && !s->tray_open && s->tray_locked) {
             scsi_check_condition(r,
                                  bdrv_is_inserted(s->qdev.conf.bs)