Add netifapi macros for set link up/down

This commit extends the netifapi macros to support netif_set_link_up
and netif_set_link_down

src/include/lwip/netifapi.h

@@ -93,13 +93,17 @@ err_t netifapi_netif_common(struct netif *netif, netifapi_void_fn voidfunc,
                             netifapi_errt_fn errtfunc);
 
 /** @ingroup netifapi_netif */
-#define netifapi_netif_remove(n)      netifapi_netif_common(n, netif_remove, NULL)
+#define netifapi_netif_remove(n)        netifapi_netif_common(n, netif_remove, NULL)
 /** @ingroup netifapi_netif */
-#define netifapi_netif_set_up(n)      netifapi_netif_common(n, netif_set_up, NULL)
+#define netifapi_netif_set_up(n)        netifapi_netif_common(n, netif_set_up, NULL)
 /** @ingroup netifapi_netif */
-#define netifapi_netif_set_down(n)    netifapi_netif_common(n, netif_set_down, NULL)
+#define netifapi_netif_set_down(n)      netifapi_netif_common(n, netif_set_down, NULL)
 /** @ingroup netifapi_netif */
-#define netifapi_netif_set_default(n) netifapi_netif_common(n, netif_set_default, NULL)
+#define netifapi_netif_set_default(n)   netifapi_netif_common(n, netif_set_default, NULL)
+/** @ingroup netifapi_netif */
+#define netifapi_netif_set_link_up(n)   netifapi_netif_common(n, netif_set_link_up, NULL)
+/** @ingroup netifapi_netif */
+#define netifapi_netif_set_link_down(n) netifapi_netif_common(n, netif_set_link_down, NULL)
 
 /**
  * @defgroup netifapi_dhcp4 DHCPv4