meta-quanta: olympus-nuvoton: iptable: save rules while bmc rebooting

The iptable needs to be preserved in order keep the rules.

Tested: Verified for Olympus platform

(From meta-quanta rev: ae01a4669bc1653ed81998573f25b8dc62a4794b)

Signed-off-by: Joseph Liu <kwliu@nuvoton.com>
Signed-off-by: Tim Lee <timlee660101@gmail.com>
Change-Id: Ic9b226f21a2526994bdf353701d0ca7b7d053d8a
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>