Adrian Chadd c9f70b7b88 [arswitch] fix up issues on the AR8327.
This correctly dumps the ethernet bridge contents on an AR8327 switch.

Tested:

* AP135 - QCA9550 + AR8327 ethernet switch:

# etherswitchcfg atu dump
 [0] c0:3f:d5:7e:6f:45: portmask 0x00000004
 [1] f6:b6:03:96:1e:ba: portmask 0x00000004
 [2] 00:03:7f:11:38:4f: portmask 0x00000040
# arp -na
? (192.168.3.170) at 00:03:7f:11:38:4f on arge0 permanent [ethernet]
? (192.168.3.12) at c0:3f:d5:7e:6f:45 on arge0 expires in 1188 seconds [ethernet]
? (192.168.3.1) at f6:b6:03:96:1e:ba on arge0 expires in 1186 seconds [ethernet]
2018-02-04 08:22:11 +00:00
..
2018-02-02 07:39:34 +00:00
2018-02-02 02:28:25 +00:00
2018-01-31 16:54:05 +00:00