net80211: add debugging information

Add more STATE / DEBUG probes and enhance the output of one in order
to track state changes triggered by "ack" (or not).
This helped to narrow down causes from drivers or the LinuxKPI 802.11
compat framework which kept us in a scan -> auth -> scan loop.

Sponsored by: The FreeBSD Foundation

(cherry picked from commit 04efa18f83d12dca2b69dd4cdb626f92e5ce64f0)