geneve: remove MODULE_ALIAS_RTNL_LINK from net/ipv4/geneve.c

This file is essentially a library for implementing the geneve
encapsulation protocol.  The file does not register any rtnl_link_ops,
so the MODULE_ALIAS_RTNL_LINK macro is inappropriate here.

Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>