wifi: ath11k: save max transmit power in vdev start response event from firmware

Save the max transmit power received in the vdev start response event from
firmware. A subsequent patch will use this to calculate the final power
value for WMI_VDEV_SET_TPC_POWER_CMDID.

Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.23

Signed-off-by: Wen Gong <quic_wgong@quicinc.com>
Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Baochen Qiang <quic_bqiang@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://msgid.link/20231218085844.2658-9-quic_bqiang@quicinc.com