openvswitch: remove duplicated include from vport-gre.c

Remove duplicated include.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Jesse Gross <jesse@nicira.com>

net/openvswitch/vport-gre.c

@@ -24,8 +24,6 @@
 #include <linux/if_tunnel.h>
 #include <linux/if_vlan.h>
 #include <linux/in.h>
-#include <linux/if_vlan.h>
-#include <linux/in.h>
 #include <linux/in_route.h>
 #include <linux/inetdevice.h>
 #include <linux/jhash.h>