ipv6: Use the existing ethernet frame type constants.

Change-Id: I6938c2c29350de760e24211e5ab77c86133104bd
diff --git a/src/net/ipv6/inet6.c b/src/net/ipv6/inet6.c
index 3caf3d0..7d7a29f 100644
--- a/src/net/ipv6/inet6.c
+++ b/src/net/ipv6/inet6.c
@@ -341,9 +341,9 @@
 
 	if (len < (ETH_HDR_LEN + IP6_HDR_LEN))
 		BAD("Bogus Header Len");
-	if (data[12] != (ETH_IP6 >> 8))
+	if (data[12] != (EthType_Ipv6 >> 8))
 		return;
-	if (data[13] != (ETH_IP6 & 0xFF))
+	if (data[13] != (EthType_Ipv6 & 0xFF))
 		return;
 
 	ip = (void *)(data + ETH_HDR_LEN);
diff --git a/src/net/ipv6/inet6.h b/src/net/ipv6/inet6.h
index e10b59b..e01b6b5 100644
--- a/src/net/ipv6/inet6.h
+++ b/src/net/ipv6/inet6.h
@@ -30,10 +30,6 @@
 extern const ip6_addr ip6_ll_all_nodes;
 extern const ip6_addr ip6_ll_all_routers;
 
-#define ETH_IP4 0x0800
-#define ETH_ARP 0x0806
-#define ETH_IP6 0x86DD
-
 #define HDR_HNH_OPT 0
 #define HDR_TCP 6
 #define HDR_UDP 17