virtio-scsi: Make virtio_scsi_free_req public

To share with dataplane code later.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index 8cab75b..c7ae83d 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -53,7 +53,7 @@
     return req;
 }
 
-static void virtio_scsi_free_req(VirtIOSCSIReq *req)
+void virtio_scsi_free_req(VirtIOSCSIReq *req)
 {
     VirtIOSCSICommon *vs = (VirtIOSCSICommon *)req->dev;