wifi: iwlwifi: mvm: cleanup MLO and non-MLO unification code

bss_info_changed() callback of mac80211 was originally in both
MLD and non-MLD API. Therefore, we extracted the common part
to a function which receives a callback structure with the
mode-specific (non-MLO\MLO) ops. Eventually, for MLO API,
bss_info_changed() callback was split into 2 callbacks:
link_info_changed() and vif_cfg_changed() so it is no longer in use
for MLO, only for non-MLO.
Remove the code that uses the mode-specific callback structure.

Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20231011130030.b65fbcdb9295.I2a64a6f1178ee0466755d728addc77acbb2ed6f4@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>