wifi: cfg80211: Fix extended KCK key length check in nl80211_set_rekey_data()

wifi: cfg80211: Fix extended KCK key length check in nl80211_set_rekey_data()

The extended KCK key length check wrongly using the KEK key attribute
for validation. Due to this GTK rekey offload is failing when the KCK
key length is 24 bytes even though the driver advertising
WIPHY_FLAG_SUPPORTS_EXT_KEK_KCK flag. Use correct attribute to fix the
same.

Fixes: 093a48d2aa4b ("cfg80211: support bigger kek/kck key length")
Signed-off-by: Shivani Baranwal <quic_shivbara@quicinc.com>
Signed-off-by: Veerendranath Jakkam <quic_vjakkam@quicinc.com>
Link: https://lore.kernel.org/r/20221206143715.1802987-2-quic_vjakkam@quicinc.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>