[NET]: Change 1500 to ETH_DATA_LEN in some files

These patches add the header linux/if_ether.h and change 1500 to
ETH_DATA_LEN in some files.

Signed-off-by: Kris Katterjohn <kjak@users.sourceforge.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index c3123c9..577d497 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -33,6 +33,7 @@
 #include <asm/uaccess.h>
 #include <linux/init.h>
 #include <linux/netfilter_ipv4.h>
+#include <linux/if_ether.h>
 
 #include <net/sock.h>
 #include <net/snmp.h>
@@ -720,7 +721,7 @@
 
 	dev->type		= ARPHRD_SIT;
 	dev->hard_header_len 	= LL_MAX_HEADER + sizeof(struct iphdr);
-	dev->mtu		= 1500 - sizeof(struct iphdr);
+	dev->mtu		= ETH_DATA_LEN - sizeof(struct iphdr);
 	dev->flags		= IFF_NOARP;
 	dev->iflink		= 0;
 	dev->addr_len		= 4;