Use MAC_ADDR_LEN in a few more places. [skip ci]
diff --git a/print-cfm.c b/print-cfm.c
index 52965a9..27e72a2 100644
--- a/print-cfm.c
+++ b/print-cfm.c
@@ -407,7 +407,7 @@
                 break;
 
             case CFM_CCM_MD_FORMAT_MAC:
-                if (md_namelength == 6) {
+                if (md_namelength == MAC_ADDR_LEN) {
                     ND_PRINT("\n\t  MAC %s", GET_ETHERADDR_STRING(md_name));
                 } else {
                     ND_PRINT("\n\t  MAC (length invalid)");
diff --git a/print-isoclns.c b/print-isoclns.c
index 44d1aa7..6762f4d 100644
--- a/print-isoclns.c
+++ b/print-isoclns.c
@@ -1298,7 +1298,7 @@
 		pptr += netal;
                 li -= netal;
 
-		if (snpal == 6)
+		if (snpal == MAC_ADDR_LEN)
 			ND_PRINT("\n\t  SNPA (length: %u): %s",
 			       snpal,
 			       GET_ETHERADDR_STRING(snpa));
diff --git a/print-sll.c b/print-sll.c
index 38db452..ad0ae7f 100644
--- a/print-sll.c
+++ b/print-sll.c
@@ -162,7 +162,7 @@
 	 * For now, we just assume 6 means Ethernet.
 	 * XXX - print others as strings of hex?
 	 */
-	if (GET_BE_U_2(sllp->sll_halen) == 6)
+	if (GET_BE_U_2(sllp->sll_halen) == MAC_ADDR_LEN)
 		ND_PRINT("%s ", GET_ETHERADDR_STRING(sllp->sll_addr));
 
 	if (!ndo->ndo_qflag) {
@@ -354,7 +354,7 @@
 	 * For now, we just assume 6 means Ethernet.
 	 * XXX - print others as strings of hex?
 	 */
-	if (GET_U_1(sllp->sll2_halen) == 6)
+	if (GET_U_1(sllp->sll2_halen) == MAC_ADDR_LEN)
 		ND_PRINT("%s ", GET_ETHERADDR_STRING(sllp->sll2_addr));
 
 	if (!ndo->ndo_qflag) {