net: sfc: Correct key_len for efx_tc_ct_zone_ht_params

net: sfc: Correct key_len for efx_tc_ct_zone_ht_params

In efx_tc_ct_zone_ht_params, the key_len was previously set to
offsetof(struct efx_tc_ct_zone, linkage). This calculation is incorrect
because it includes any padding between the zone field and the linkage
field due to structure alignment, which can vary between systems.

This patch updates key_len to use sizeof_field(struct efx_tc_ct_zone, zone)
, ensuring that the hash table correctly uses the zone as the key. This fix
prevents potential hash lookup errors and improves connection tracking
reliability.

Fixes: c3bb5c6acd4e ("sfc: functions to register for conntrack zone offload")
Signed-off-by: Liang Jie <liangjie@lixiang.com>
Acked-by: Edward Cree <ecree.xilinx@gmail.com>
Link: https://patch.msgid.link/20241230093709.3226854-1-buaajxlj@163.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>