hw/scsi: Don't increment a boolean value

This fixes a warning from cppcheck.
Signed-off-by: NStefan Weil <sw@weilnetz.de>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

hw/scsi/vmw_pvscsi.c

@@ -389,7 +389,7 @@ pvscsi_process_completion_queue(void *opaque)
         QTAILQ_REMOVE(&s->completion_queue, pvscsi_req, next);
         pvscsi_cmp_ring_put(s, &pvscsi_req->cmp);
         g_free(pvscsi_req);
-        has_completed++;
+        has_completed = true;
     }
 
     if (has_completed) {