net/if_arp.h: add ARPHRD_RAWIP from linux v4.14

new in linux commmit cdf4969c42a6c1a376dd03a9e846cf638d3cd4b1

include/net/if_arp.h

@@ -59,6 +59,7 @@ struct arphdr {
 #define ARPHRD_LAPB	516
 #define ARPHRD_DDCMP	517
 #define	ARPHRD_RAWHDLC	518
+#define ARPHRD_RAWIP	519
 
 #define ARPHRD_TUNNEL	768
 #define ARPHRD_TUNNEL6	769