odp-util: Add missing comma after gtpu attributes.

Currently flows are printed like this:
        'tunnel(gtpu(flags=0x7f,msgtype=0)flags(0))'
With this change:
        'tunnel(gtpu(flags=0x7f,msgtype=0),flags(0))'

Fixes: 3c6d05a ("userspace: Add GTP-U support.")
Acked-by: Yi Yang <yangyi01@inspur.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>

lib/odp-util.c

@@ -3971,7 +3971,7 @@ format_odp_tun_attr(const struct nlattr *attr, const struct nlattr *mask_attr,
         case OVS_TUNNEL_KEY_ATTR_GTPU_OPTS:
             ds_put_cstr(ds, "gtpu(");
             format_odp_tun_gtpu_opt(a, ma, ds, verbose);
-            ds_put_cstr(ds, ")");
+            ds_put_cstr(ds, "),");
             break;
         case __OVS_TUNNEL_KEY_ATTR_MAX:
         default: