[PATCH][next] wifi: mac80211: ieee80211_i: Avoid dozens of -Wflex-array-member-not-at-end warnings

["Gustavo A. R. Silva" <gustavoars@kernel.org>]

-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.

Move the conflicting declaration to the end of the structure and add
a code comment. Notice that `struct ieee80211_chanctx_conf` is a
flexible structure --a structure that contains a flexible-array member.

Fix 50 of the following warnings:

net/mac80211/ieee80211_i.h:895:39: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 net/mac80211/ieee80211_i.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index e7815ffeaf30..c65adbdf2166 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -892,9 +892,10 @@ struct ieee80211_chanctx {
 	/* temporary data for search algorithm etc. */
 	struct ieee80211_chan_req req;
 
-	struct ieee80211_chanctx_conf conf;
-
 	bool radar_detected;
+
+	/* MUST be last - ends in a flexible-array member. */
+	struct ieee80211_chanctx_conf conf;
 };
 
 struct mac80211_qos_map {
-- 
2.34.1