add UDP_ENCAP_GTP0, UDP_ENCAP_GTP1U from linux v4.7 to netinet/udp.h

for GPRS tunneling protocol, new in linux commit
459aa660eb1d8ce67080da1983bb81d716aa5a69

include/netinet/udp.h

@@ -28,6 +28,8 @@ struct udphdr {
 #define UDP_ENCAP_ESPINUDP_NON_IKE 1
 #define UDP_ENCAP_ESPINUDP	2
 #define UDP_ENCAP_L2TPINUDP	3
+#define UDP_ENCAP_GTP0		4
+#define UDP_ENCAP_GTP1U		5
 
 #define SOL_UDP            17