mlxsw: spectrum_ipip: Add a forgotten include

struct ip_tunnel_parm, which is used in spectrum_ipip.h, is defined in
if_tunnel.h. However, the former neglects to include the latter.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum_ipip.h

@@ -37,6 +37,7 @@
 
 #include "spectrum_router.h"
 #include <net/ip_fib.h>
+#include <linux/if_tunnel.h>
 
 struct ip_tunnel_parm
 mlxsw_sp_ipip_netdev_parms(const struct net_device *ol_dev);