wifi: mac80211: fix TTLM teardown work

The worker calculates the wrong sdata pointer, so if it ever
runs, it'll crash. Fix that.

Fixes: a17a58ad ("wifi: mac80211: add support for tearing down negotiated TTLM")
Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240506211853.e6471800c76d.I8b7c2d6984c89a11cd33d1a610e9645fa965f6e1@changeid


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