bonding: fix netlink msg size

Add missing space for IFLA_BOND_ARP_IP_TARGET nest header.

Signed-off-by: Scott Feldman <sfeldma@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bonding/bond_netlink.c b/drivers/net/bonding/bond_netlink.c
index 1b4013b..555c783 100644
--- a/drivers/net/bonding/bond_netlink.c
+++ b/drivers/net/bonding/bond_netlink.c
@@ -296,6 +296,7 @@
 		nla_total_size(sizeof(u8)) +	/* IFLA_BOND_USE_CARRIER */
 		nla_total_size(sizeof(u32)) +	/* IFLA_BOND_ARP_INTERVAL */
 						/* IFLA_BOND_ARP_IP_TARGET */
+		nla_total_size(sizeof(struct nlattr)) +
 		nla_total_size(sizeof(u32)) * BOND_MAX_ARP_TARGETS +
 		nla_total_size(sizeof(u32)) +	/* IFLA_BOND_ARP_VALIDATE */
 		nla_total_size(sizeof(u32)) +	/* IFLA_BOND_ARP_ALL_TARGETS */