wifi: iwlwifi: mvm: don't change BA sessions during restart

During restart, we haven't added BA sessions, so we also cannot
change them to switch between links when that happens in restart.
Short-circuit the appropriate function.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240320232419.70ba08540db0.Ic604d384e660c755308a49a79d3f7e78bc27597c@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>