wifi: iwlwifi: mvm: fix link ID management

On older (pre-MLD API) devices, we started also calling
iwl_mvm_set_link_mapping()/iwl_mvm_unset_link_mapping(),
but of course not also iwl_mvm_remove_link(). Since the
link ID was only released in iwl_mvm_remove_link() this
causes us to run out of FW link IDs very quickly. Fix
it by releasing the link ID correctly.

Fixes: a8b5d480

 ("wifi: iwlwifi: mvm: Configure the link mapping for non-MLD FW")
Link: https://msgid.link/20240420154435.dce72db5d5e3.Ic40b454b24f1c7b380a1eedf67455d9cf2f58541@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>