mac80211: fix throughput LED trigger

As I was testing with hwsim, I missed that my previous commit to
make LED work depend on activation broke the code because I missed
removing the old trigger struct and some code was still using it,
now erroneously, causing crashes.

Fix this by always using the correct struct.

Reported-by: Felix Fietkau <nbd@openwrt.org>
Tested-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>