netfilter: conntrack: remove duplicated include from nf_conntrack_proto_udp.c

Remove duplicated include.

Fixes: c779e849608a ("netfilter: conntrack: remove get_timeout() indirection")
Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_conntrack_proto_udp.c

@@ -393,4 +393,3 @@ const struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite6 =
 };
 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udplite6);
 #endif
-#include <net/netfilter/nf_conntrack_timeout.h>