netns: rename peernet2id() to peernet2id_alloc()

In a following commit, a new function will be introduced to only lookup for
a nsid (no allocation if the nsid doesn't exist). To avoid confusion, the
existing function is renamed.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 3517ab0a..48341ae 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -336,7 +336,7 @@
 
 	if (!net_eq(dev_net(vxlan->dev), vxlan->net) &&
 	    nla_put_s32(skb, NDA_LINK_NETNSID,
-			peernet2id(dev_net(vxlan->dev), vxlan->net)))
+			peernet2id_alloc(dev_net(vxlan->dev), vxlan->net)))
 		goto nla_put_failure;
 
 	if (send_eth && nla_put(skb, NDA_LLADDR, ETH_ALEN, &fdb->eth_addr))