wifi: mac80211: Add link iteration macro for link data

Currently before iterating through valid links we are utilizing
open-coding when checking if vif valid_links is a non-zero value.

Add new macro, for_each_link_data(), which iterates through link_id
and checks if it is set on vif valid_links. If it is a valid link then
access link data for that link id.

Signed-off-by: Muna Sinada <muna.sinada@oss.qualcomm.com>
Link: https://patch.msgid.link/20250325213125.1509362-2-muna.sinada@oss.qualcomm.com


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