change the comment of vti6_ioctl

The comment of vti6_ioctl() is wrong. which use vti6_tnl_ioctl
instead of vti6_ioctl.
Signed-off-by: NSun Lianwen <sunlw.fnst@cn.fujitsu.com>
Signed-off-by: NSteffen Klassert <steffen.klassert@secunet.com>

net/ipv6/ip6_vti.c

@@ -743,7 +743,7 @@ vti6_parm_to_user(struct ip6_tnl_parm2 *u, const struct __ip6_tnl_parm *p)
 }
 
 /**
- * vti6_tnl_ioctl - configure vti6 tunnels from userspace
+ * vti6_ioctl - configure vti6 tunnels from userspace
  *   @dev: virtual device associated with tunnel
  *   @ifr: parameters passed from userspace
  *   @cmd: command to be performed