[NETFILTER]: Don't invoke okfn in CONFIG_NETFILTER=n variant of nf_hook()

nf_hook() is supposed to call the netfilter hook and return control of the
packet back to the caller in case it may pass, the okfn is only used for
queueing.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>