virtio: make config_ops const

It is just a table of function pointers, make it const for cleanliness and security
reasons.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c
index fc92ccb..b3256ff 100644
--- a/drivers/lguest/lguest_device.c
+++ b/drivers/lguest/lguest_device.c
@@ -396,7 +396,7 @@
 }
 
 /* The ops structure which hooks everything together. */
-static struct virtio_config_ops lguest_config_ops = {
+static const struct virtio_config_ops lguest_config_ops = {
 	.get_features = lg_get_features,
 	.finalize_features = lg_finalize_features,
 	.get = lg_get,