[IPV6] ADDRLABEL: Sparse: Make several functions static.

Fix following sparse warnings:
| net/ipv6/addrlabel.c:172:25: warning: symbol 'ip6addrlbl_alloc' was not declared. Should it be static?
| net/ipv6/addrlabel.c:219:5: warning: symbol '__ip6addrlbl_add' was not declared. Should it be static?
| net/ipv6/addrlabel.c:260:5: warning: symbol 'ip6addrlbl_add' was not declared. Should it be static?
| net/ipv6/addrlabel.c:285:5: warning: symbol '__ip6addrlbl_del' was not declared. Should it be static?
| net/ipv6/addrlabel.c:311:5: warning: symbol 'ip6addrlbl_del' was not declared. Should it be static?
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

net/ipv6/addrlabel.c

@@ -169,7 +169,7 @@ u32 ipv6_addr_label(const struct in6_addr *addr, int type, int ifindex)
 }
 
 /* allocate one entry */
-struct ip6addrlbl_entry *ip6addrlbl_alloc(const struct in6_addr *prefix,
+static struct ip6addrlbl_entry *ip6addrlbl_alloc(const struct in6_addr *prefix,
 						 int prefixlen, int ifindex,
 						 u32 label)
 {
@@ -216,7 +216,7 @@ struct ip6addrlbl_entry *ip6addrlbl_alloc(const struct in6_addr *prefix,
 }
 
 /* add a label */
-int __ip6addrlbl_add(struct ip6addrlbl_entry *newp, int replace)
+static int __ip6addrlbl_add(struct ip6addrlbl_entry *newp, int replace)
 {
 	int ret = 0;
 
@@ -257,7 +257,7 @@ int __ip6addrlbl_add(struct ip6addrlbl_entry *newp, int replace)
 }
 
 /* add a label */
-int ip6addrlbl_add(const struct in6_addr *prefix, int prefixlen,
+static int ip6addrlbl_add(const struct in6_addr *prefix, int prefixlen,
 			  int ifindex, u32 label, int replace)
 {
 	struct ip6addrlbl_entry *newp;
@@ -282,7 +282,7 @@ int ip6addrlbl_add(const struct in6_addr *prefix, int prefixlen,
 }
 
 /* remove a label */
-int __ip6addrlbl_del(const struct in6_addr *prefix, int prefixlen,
+static int __ip6addrlbl_del(const struct in6_addr *prefix, int prefixlen,
 			    int ifindex)
 {
 	struct ip6addrlbl_entry *p = NULL;
@@ -308,7 +308,7 @@ int __ip6addrlbl_del(const struct in6_addr *prefix, int prefixlen,
 	return ret;
 }
 
-int ip6addrlbl_del(const struct in6_addr *prefix, int prefixlen,
+static int ip6addrlbl_del(const struct in6_addr *prefix, int prefixlen,
 			  int ifindex)
 {
 	struct in6_addr prefix_buf;