wifi: ath12k: Set EHT fixed rates for associated STAs

wifi: ath12k: Set EHT fixed rates for associated STAs

Fixed rate is set for STAs that are associated. This will be done
during association or with ath12k_sta_rc_update_wk().

Add EHT fixed rate setting for STAs by adding call to
ath12k_mac_set_peer_eht_fixed_rate() during the times fixed rate is
set for STAs. This new function sets EHT fixed rate for a peer, which
sends WMI command with the updated MCS/NSS rate using
WMI_PEER_PARAM_FIXED_RATE command id.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1

Co-developed-by: Aaradhana Sahu <quic_aarasahu@quicinc.com>
Signed-off-by: Aaradhana Sahu <quic_aarasahu@quicinc.com>
Signed-off-by: Muna Sinada <muna.sinada@oss.qualcomm.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Link: https://patch.msgid.link/20251024001928.257356-7-muna.sinada@oss.qualcomm.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>