netfilter: nf_nat: fix conversion to non-atomic bit ops
My previous patch (netfilter: nf_nat: don't use atomic bit operation)
made a mistake when converting atomic_set to a normal bit 'or'.
IPS_*_BIT should be replaced with IPS_*.
Signed-off-by: Changli Gao <xiaosuo@gmail.com> Cc: Tim Gardner <tim.gardner@canonical.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Patrick McHardy <kaber@trash.net>