mpls: Change reserved label names to be consistent with netbsd

Since these are now visible to userspace it is nice to be consistent
with BSD (sys/netmpls/mpls.h in netBSD).

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index b6eb761..7b3f732 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -647,7 +647,7 @@
 			return -EINVAL;
 
 		switch (dec.label) {
-		case MPLS_LABEL_IMPLICIT_NULL:
+		case MPLS_LABEL_IMPLNULL:
 			/* RFC3032: This is a label that an LSR may
 			 * assign and distribute, but which never
 			 * actually appears in the encapsulation.
@@ -935,7 +935,7 @@
 	}
 
 	/* In case the predefined labels need to be populated */
-	if (limit > MPLS_LABEL_IPV4_EXPLICIT_NULL) {
+	if (limit > MPLS_LABEL_IPV4NULL) {
 		struct net_device *lo = net->loopback_dev;
 		rt0 = mpls_rt_alloc(lo->addr_len);
 		if (!rt0)
@@ -945,7 +945,7 @@
 		rt0->rt_via_table = NEIGH_LINK_TABLE;
 		memcpy(rt0->rt_via, lo->dev_addr, lo->addr_len);
 	}
-	if (limit > MPLS_LABEL_IPV6_EXPLICIT_NULL) {
+	if (limit > MPLS_LABEL_IPV6NULL) {
 		struct net_device *lo = net->loopback_dev;
 		rt2 = mpls_rt_alloc(lo->addr_len);
 		if (!rt2)
@@ -973,15 +973,15 @@
 	memcpy(labels, old, cp_size);
 
 	/* If needed set the predefined labels */
-	if ((old_limit <= MPLS_LABEL_IPV6_EXPLICIT_NULL) &&
-	    (limit > MPLS_LABEL_IPV6_EXPLICIT_NULL)) {
-		RCU_INIT_POINTER(labels[MPLS_LABEL_IPV6_EXPLICIT_NULL], rt2);
+	if ((old_limit <= MPLS_LABEL_IPV6NULL) &&
+	    (limit > MPLS_LABEL_IPV6NULL)) {
+		RCU_INIT_POINTER(labels[MPLS_LABEL_IPV6NULL], rt2);
 		rt2 = NULL;
 	}
 
-	if ((old_limit <= MPLS_LABEL_IPV4_EXPLICIT_NULL) &&
-	    (limit > MPLS_LABEL_IPV4_EXPLICIT_NULL)) {
-		RCU_INIT_POINTER(labels[MPLS_LABEL_IPV4_EXPLICIT_NULL], rt0);
+	if ((old_limit <= MPLS_LABEL_IPV4NULL) &&
+	    (limit > MPLS_LABEL_IPV4NULL)) {
+		RCU_INIT_POINTER(labels[MPLS_LABEL_IPV4NULL], rt0);
 		rt0 = NULL;
 	}