wifi: ath12k: fix the fetching of combined rssi

wifi: ath12k: fix the fetching of combined rssi

Currently, host fetches combined rssi from rssi_comb in struct
hal_rx_phyrx_rssi_legacy_info.

rssi_comb is 8th to 15th bits of the second to last variable.
rssi_comb_ppdu is the 0th to 7th of the last variable.

When bandwidth = 20MHz, rssi_comb = rssi_comb_ppdu. But when bandwidth >
20MHz, rssi_comb < rssi_comb_ppdu because rssi_comb only includes power
of primary 20 MHz while rssi_comb_ppdu includes power of active
RUs/subchannels. So should fetch combined rssi from rssi_comb_ppdu.

Also related macro definitions are too long, rename them.

Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3
Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.4.1-00199-QCAHKSWPL_SILICONZ-1

Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
Signed-off-by: Kang Yang <kang.yang@oss.qualcomm.com>
Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Link: https://patch.msgid.link/20250722095934.67-4-kang.yang@oss.qualcomm.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>