[IPV6]: fix ipv6_saddr_score struct element

The scope element in the ipv6_saddr_score struct used in 
ipv6_dev_get_saddr() is an unsigned integer, but __ipv6_addr_src_scope() 
returns a signed integer (and can return -1).

Signed-off-by: Brian Haley <brian.haley@hp.com>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index b7d8822..19727d9 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -822,7 +822,7 @@
 	int		addr_type;
 	unsigned int	attrs;
 	int		matchlen;
-	unsigned int	scope;
+	int		scope;
 	unsigned int	rule;
 };