wifi: ath12k: fix invalid AMPDU factor calculation in ath12k_peer_assoc_h_he()

Currently ampdu_factor is wrongly calculated in ath12k_peer_assoc_h_he(), fix it.

This is found during code review.

Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0-03427-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.15378.4

Fixes: d8899132 ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
Signed-off-by: Baochen Qiang <quic_bqiang@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://patch.msgid.link/20240710021819.87216-1-quic_bqiang@quicinc.com