wifi: iwlwifi: mvm: don't track used links separately

wifi: iwlwifi: mvm: don't track used links separately

We track which link is using which FW link ID, so there
really isn't a need to separately track which link IDs
are in use. Remove that code and check the table when
looking for a new link ID to use.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240512072733.1a67d8af815f.Ie642c12dce3ab55c688abd9a25918569e83e558a@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>