wifi: iwlwifi: fix aux ROC time event iterator usage

wifi: iwlwifi: fix aux ROC time event iterator usage

The list_for_each_entry() iterator must not be used outside the loop.
Even though we break and check for NULL, doing so still violates kernel
iteration rules and triggers Coccinelle's use_after_iter.cocci warning.

Cache the matched entry in aux_roc_te and use it consistently after the
loop. This follows iterator best practices, resolves the warning, and
makes the code more maintainable.

Signed-off-by: Junjie Cao <junjie.cao@intel.com>
Link: https://patch.msgid.link/20251016014919.383565-1-junjie.cao@intel.com
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>