Make some conditional compilation consistent

include/nuttx/net/ip.h

@@ -230,11 +230,11 @@ EXTERN const net_ipv6addr_t g_ipv6_allzeroaddr; /* An address of all zeroes */
 #if defined(CONFIG_NET_ICMPv6_AUTOCONF) || defined(CONFIG_NET_ICMPv6_ROUTER)
 EXTERN const net_ipv6addr_t g_ipv6_allnodes;    /* All link local nodes */
 EXTERN const net_ipv6addr_t g_ipv6_allrouters;  /* All link local routers */
-#endif
 #ifdef CONFIG_NET_ICMPv6_AUTOCONF
 EXTERN const net_ipv6addr_t g_ipv6_llnetmask;   /* Netmask for local link address */
 #endif
 #endif
+#endif
 
 /****************************************************************************
  * Public Function Prototypes

net/devif/devif_initialize.c

@@ -112,6 +112,7 @@ const net_ipv6addr_t g_ipv6_allrouters =  /* All link local routers */
   HTONS(0x0002)
 };
 
+#ifdef CONFIG_NET_ICMPv6_AUTOCONF
 /* Link-Local Address: Link-local addresses have "1111 1110 10" for the
  * first ten bits followed by 54 zeroes and then the 64 bit interface
  * identifier (typically derived from the data link layer address).
@@ -121,6 +122,7 @@ const net_ipv6addr_t g_ipv6_llnetmask =   /* Netmask for local link address */
 {
   0xffff, 0xffff, 0xffff, 0xffff, 0x0000, 0x0000, 0x0000, 0x0000
 };
+#endif /* CONFIG_NET_ICMPv6_AUTOCONF */
 
 #ifdef CONFIG_NET_ETHERNET