wifi: ath12k: Fix memory corruption during MLO multicast tx

The struct sk_buff's control buffer is shared by mac80211's struct
ieee80211_tx_info and ath12k's struct ath12k_skb_cb. When the driver wants
to transmit an skb, it caches all the mac80211 specific information from
struct ieee80211_tx_info, then performs a memset on the control buffer
before writing the ath12k specific information using struct ath12k_skb_cb.
However, during multicast transmission, the key is being filled into the
driver data, which overwrites some crucial members like link_id and flags
in struct ath12k_skb_cb. This causes issue when driver access these fields
during ath12k_dp_tx(). Fix this issue by removing the key filling logic
during MLO multicast tx, as it is not used anywhere in the tx path.

Signed-off-by: P Praneesh <quic_ppranees@quicinc.com>
Signed-off-by: Raj Kumar Bhagat <quic_rajkbhag@quicinc.com>
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>