brcmwifi: don't use AutoDict

The AutoDict for the AssociatedDeviceList has triggered
a series of issues, described in b/29127321 and b/33414470.
Stop using AutoDict, instead make a dict() of all associated
devices similar to how binwifi.py does it.

Fixes b/33414470

Change-Id: I362005ff57410e7dd0fec958256783ecd74e46f2
2 files changed