Fix coding style NO_SYS example code

(cherry picked from commit b9a40a5163b78cf186169fc878f5a655fee20261)

doc/NO_SYS_SampleCode.c

@@ -1,4 +1,5 @@
-void eth_mac_irq()
+void
+eth_mac_irq()
 {
   /* Service MAC IRQ here */
 
@@ -17,7 +18,8 @@ void eth_mac_irq()
   }
 }
 
-static err_t netif_output(struct netif *netif, struct pbuf *p)
+static err_t 
+netif_output(struct netif *netif, struct pbuf *p)
 {
   LINK_STATS_INC(link.xmit);
 
@@ -38,12 +40,14 @@ static err_t netif_output(struct netif *netif, struct pbuf *p)
   return ERR_OK;
 }
 
-static void netif_status_callback(struct netif *netif)
+static void 
+netif_status_callback(struct netif *netif)
 {
   printf("netif status changed %s\n", ip4addr_ntoa(netif_ip4_addr(netif)));
 }
 
-static err_t netif_init(struct netif *netif)
+static err_t 
+netif_init(struct netif *netif)
 {
   netif->linkoutput = netif_output;
   netif->output     = etharp_output;
@@ -58,7 +62,8 @@ static err_t netif_init(struct netif *netif)
   return ERR_OK;
 }
 
-void main(void)
+void 
+main(void)
 {
   struct netif netif;