wifi: ath12k: add parse of transmit power envelope element

wifi: ath12k: add parse of transmit power envelope element

The Transmit Power Envelope element conveys the local maximum transmit
power for various transmission bandwidths, this element is present in
various frames, e.g. beacon and probe response etc, transmitted by AP.
A station shall determine a local maximum transmit power from it.

So parse and save them for later use.

Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Signed-off-by: Baochen Qiang <quic_bqiang@quicinc.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Link: https://patch.msgid.link/20250418-ath12k-6g-lp-vlp-v1-11-c869c86cad60@quicinc.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>