MAINTAINERS: virtio-dev is subscribers only

virtio-dev mailing list is for subscribers only according to the
returned message after trying to send to it.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

MAINTAINERS

@@ -9385,7 +9385,7 @@ F:	include/media/videobuf2-*
 
 VIRTIO CONSOLE DRIVER
 M:	Amit Shah <amit.shah@redhat.com>
-L:	virtio-dev@lists.oasis-open.org
+L:	virtio-dev@lists.oasis-open.org (subscribers-only)
 L:	virtualization@lists.linux-foundation.org
 S:	Maintained
 F:	drivers/char/virtio_console.c
@@ -9395,7 +9395,7 @@ F:	include/uapi/linux/virtio_console.h
 VIRTIO CORE, NET AND BLOCK DRIVERS
 M:	Rusty Russell <rusty@rustcorp.com.au>
 M:	"Michael S. Tsirkin" <mst@redhat.com>
-L:	virtio-dev@lists.oasis-open.org
+L:	virtio-dev@lists.oasis-open.org (subscribers-only)
 L:	virtualization@lists.linux-foundation.org
 S:	Maintained
 F:	drivers/virtio/
@@ -9408,7 +9408,7 @@ F:	include/uapi/linux/virtio_*.h
 VIRTIO HOST (VHOST)
 M:	"Michael S. Tsirkin" <mst@redhat.com>
 L:	kvm@vger.kernel.org
-L:	virtio-dev@lists.oasis-open.org
+L:	virtio-dev@lists.oasis-open.org (subscribers-only)
 L:	virtualization@lists.linux-foundation.org
 L:	netdev@vger.kernel.org
 S:	Maintained