[][MAC80211][hnat][Fix DL floodind issue for the C50 UDP BiDi test]

[Description]
Fix DL floodind issue for the C50 UDP BiDi test.

Scenario: LAN to WLAN
Topology: C50 port 9 <-> Switch LAN3 <-> WiFi <-> CS0 STA
          C50 port 8 <-> Switch LAN2

When the test time is longer than 300 seconds, the MAC table of the
switch will be aged out. Therefore, the packet will be flooded to the
all backbone PCs that connect with switch.

If without this patch, the C50 might encounter DL flooding issue.

[Release-log]
N/A


Change-Id: I2d92999d1a2568ee6ca37b9a840dfe1424d281dd
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/7367966
1 file changed