wifi: iwlwifi: mvm: Remove unused iwl_mvm_ftm_*_add_pasn_sta functions

iwl_mvm_ftm_respoder_add_pasn_sta() and
iwl_mvm_ftm_resp_remove_pasn_sta() were added in 2020 by
commit be82ecd3 ("iwlwifi: mvm: add an option to add PASN station")
but have remained unused.

Remove them.

After that removal iwl_mvm_add_pasn_sta() is now unused.
Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://patch.msgid.link/20241223013202.340180-4-linux@treblig.org