[iwm] Adjust if_iwm_sta.h prototypes, don't pass iwm_node to rm_sta().

• Since a RUN -> INIT/SCAN transition seems to immediately destroy the ieee80211_node for the AP, we can't read the in_assoc value from there. Instead just directly pass that information via a boolean_t argument.

• Adds iwm_mvm_rm_sta_id() function, which just unconditionally removes the station from the firmware.

• The iwm_mvm_rm_sta() function shouldn't actually remove the station from firmware when we are still associated (i.e. during a RUN -> INIT/SCAN transition).
  • So when disassociating we will first call iwm_mvm_rm_sta() to drain the queues/fifos. Later during disassociation we will then use iwm_mvm_rm_sta_id() to actually remove the station.

Inspired-By: Linux iwlwifi

Obtained from: dragonflybsd.git 81b3c1fe9122fa22f33d97103039cc375f656231