virtio ids: fix comment for virtio-rng

It's virtio-rng, not virtio-ring.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

include/linux/virtio_ids.h

@@ -32,7 +32,7 @@
 #define VIRTIO_ID_NET		1 /* virtio net */
 #define VIRTIO_ID_BLOCK		2 /* virtio block */
 #define VIRTIO_ID_CONSOLE	3 /* virtio console */
-#define VIRTIO_ID_RNG		4 /* virtio ring */
+#define VIRTIO_ID_RNG		4 /* virtio rng */
 #define VIRTIO_ID_BALLOON	5 /* virtio balloon */
 #define VIRTIO_ID_RPMSG		7 /* virtio remote processor messaging */
 #define VIRTIO_ID_SCSI		8 /* virtio scsi */