[PATCH v2][next] sched: act_ct: avoid -Wflex-array-member-not-at-end warning

["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.

Remove unnecessary flex-array member `pad[]` and refactor the related
code a bit.

Fix the following warning:
net/sched/act_ct.c:57:29: 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>
---
Changes in v2:
 - Remove flex array. (Jakub).

 net/sched/act_ct.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c
index 3ba8e7e739b5..2197eb625658 100644
--- a/net/sched/act_ct.c
+++ b/net/sched/act_ct.c
@@ -44,8 +44,6 @@ static DEFINE_MUTEX(zones_mutex);
 struct zones_ht_key {
 	struct net *net;
 	u16 zone;
-	/* Note : pad[] must be the last field. */
-	u8  pad[];
 };
 
 struct tcf_ct_flow_table {
@@ -62,7 +60,7 @@ struct tcf_ct_flow_table {
 static const struct rhashtable_params zones_params = {
 	.head_offset = offsetof(struct tcf_ct_flow_table, node),
 	.key_offset = offsetof(struct tcf_ct_flow_table, key),
-	.key_len = offsetof(struct zones_ht_key, pad),
+	.key_len = offsetofend(struct zones_ht_key, zone),
 	.automatic_shrinking = true,
 };
 
-- 
2.34.1