[NETFILTER]: nf_conntrack_h3223: sparse fixes

Sparse complains when a function is not really static. Putting static
on the function prototype is not enough.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>