gtp: add genl family modules alias

Auto-load the module when userspace asks for the gtp netlink
family.
Signed-off-by: NAndreas Schultz <aschultz@tpip.net>
Acked-by: NHarald Welte <laforge@netfilter.org>
Acked-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/gtp.c

@@ -1376,3 +1376,4 @@ MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Harald Welte <hwelte@sysmocom.de>");
 MODULE_DESCRIPTION("Interface driver for GTP encapsulated traffic");
 MODULE_ALIAS_RTNL_LINK("gtp");
+MODULE_ALIAS_GENL_FAMILY("gtp");