wifi: mac80211: Fix uninitialized variable with __free() in ieee80211_ml_epcs()

The cleanup attribute runs kfree() when the variable goes out of scope.
There is a possibility that the link_elems variable is uninitialized
if the loop ends before an assignment is made to this variable.
This leads to uninitialized variable bug.

Fix this by assigning link_elems to NULL.

Signed-off-by: Pagadala Yesu Anjaneyulu <pagadala.yesu.anjaneyulu@intel.com>
Reviewed-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250609213231.eeacd3738a7b.I0f876fa1359daeec47ab3aef098255a9c23efd70@changeid


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