wifi: mac80211: finish link init before RCU publish

wifi: mac80211: finish link init before RCU publish

[ Upstream commit d87c3ca0f8f1ca4c25f2ed819e954952f4d8d709 ]

Since the link/conf pointers can be accessed without any
protection other than RCU, make sure the data is actually
set up before publishing the structures.

Fixes: b2e8434f1829 ("wifi: mac80211: set up/tear down client vif links properly")
Link: https://patch.msgid.link/20250624130749.9a308b713c74.I4a80f5eead112a38730939ea591d2e275c721256@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>