netconf: add macro to represent all attributes

This patch adds macro NETCONFA_ALL to represent all type of netconf
attributes for IPv4 and IPv6.

Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/netconf.h b/include/uapi/linux/netconf.h
index 23cbd34..45dfad5 100644
--- a/include/uapi/linux/netconf.h
+++ b/include/uapi/linux/netconf.h
@@ -19,6 +19,7 @@
 	__NETCONFA_MAX
 };
 #define NETCONFA_MAX	(__NETCONFA_MAX - 1)
+#define NETCONFA_ALL	-1
 
 #define NETCONFA_IFINDEX_ALL		-1
 #define NETCONFA_IFINDEX_DEFAULT	-2