net: Rename the dst_opt default_mtu method to mtu

We plan to invoke the dst_opt->default_mtu() method unconditioally
from dst_mtu(). So rename the method to dst_opt->mtu() to match
the name with the new meaning.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/xfrm/xfrm_policy.c

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 552df27..b8be51e 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2382,7 +2382,7 @@
 	return dst_metric_advmss(dst->path);
 }
 
-static unsigned int xfrm_default_mtu(const struct dst_entry *dst)
+static unsigned int xfrm_mtu(const struct dst_entry *dst)
 {
 	return dst_mtu(dst->path);
 }
@@ -2411,8 +2411,8 @@
 			dst_ops->check = xfrm_dst_check;
 		if (likely(dst_ops->default_advmss == NULL))
 			dst_ops->default_advmss = xfrm_default_advmss;
-		if (likely(dst_ops->default_mtu == NULL))
-			dst_ops->default_mtu = xfrm_default_mtu;
+		if (likely(dst_ops->mtu == NULL))
+			dst_ops->mtu = xfrm_mtu;
 		if (likely(dst_ops->negative_advice == NULL))
 			dst_ops->negative_advice = xfrm_negative_advice;
 		if (likely(dst_ops->link_failure == NULL))