wifi: ath12k: Refactor the monitor channel context procedure

wifi: ath12k: Refactor the monitor channel context procedure

Currently, the monitor start procedure use the iteration callback to pick
the last available channel definition in the mac80211 hardware. This
approach is incorrect for the single wiphy model, as it holds multiple
radio/link channel contexts within the same mac80211 hardware. To fix this,
change the iteration callback to pick the specific channel context for the
given radio/link. This approach makes the monitor start procedure
compatible with both multi wiphy and single wiphy models.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.3.1-00173-QCAHKSWPL_SILICONZ-1
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Signed-off-by: Karthikeyan Periyasamy <quic_periyasa@quicinc.com>
Link: https://patch.msgid.link/20250324062518.2752822-9-quic_periyasa@quicinc.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>