scsi: Pass size to scsi_bus_new()

To be passed to qbus_create_inplace().

Use DEVICE() casts instead of direct parent field access.

Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
diff --git a/include/hw/scsi/scsi.h b/include/hw/scsi/scsi.h
index 8786531..1b66510 100644
--- a/include/hw/scsi/scsi.h
+++ b/include/hw/scsi/scsi.h
@@ -152,8 +152,8 @@
     const SCSIBusInfo *info;
 };
 
-void scsi_bus_new(SCSIBus *bus, DeviceState *host, const SCSIBusInfo *info,
-                  const char *bus_name);
+void scsi_bus_new(SCSIBus *bus, size_t bus_size, DeviceState *host,
+                  const SCSIBusInfo *info, const char *bus_name);
 
 static inline SCSIBus *scsi_bus_from_device(SCSIDevice *d)
 {