tunnels: fix netns vs proto registration ordering

Same stuff as in ip_gre patch: receive hook can be called before netns
setup is done, oopsing in net_generic().

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
static inline unsigned xfrm6_tunnel_spi_hash_byspi(u32 spi)
{
 	return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
 }

static inline unsigned xfrm6_tunnel_spi_hash_byspi(u32 spi)
{
 	return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
 }
