wifi: ath12k: Move MU user processing to Wi-Fi 7 module

wifi: ath12k: Move MU user processing to Wi-Fi 7 module

Move Wi-Fi 7-specific monitor functionality out of ath12k common code
into the Wi-Fi 7 module to improve modularity.

Move and rename the following MU user processing functions to
wifi7/dp_mon.c with the ath12k_wifi7_ prefix:
- ath12k_dp_mon_rx_handle_ofdma_info()
- ath12k_dp_mon_rx_populate_mu_user_info()
- ath12k_dp_mon_hal_rx_parse_user_info()

Move the helper functions hal_rx_mon_hal_ru_size_to_ath12k_ru_size and
hal_rx_ul_ofdma_ru_size_to_width to the Wi-Fi 7 module, and export the
helpers required by the ath12k_wifi7 code. Isolate the parsing of
MU-specific user information within the Wi-Fi 7 module to keep
common code generic.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.5-01651-QCAHKSWPL_SILICONZ-1

Signed-off-by: Alok Singh <quic_aloksing@quicinc.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Link: https://patch.msgid.link/20251110103713.3484779-11-quic_aloksing@quicinc.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>