wifi: ath12k: fix link valid field initialization in the monitor Rx

wifi: ath12k: fix link valid field initialization in the monitor Rx

Currently, the link_valid field is not initialized in the monitor Rx path.
This can result in random values for the link_valid and link_id leads to
undefined behaviour in mac80211. Therefore, initialize the link_valid
field in the monitor Rx path.

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

Signed-off-by: Hari Chandrakanthan <quic_haric@quicinc.com>
Tested-by: Nicolas Escande <nico.escande@gmail.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Signed-off-by: Karthikeyan Periyasamy <quic_periyasa@quicinc.com>
Link: https://patch.msgid.link/20250324062518.2752822-2-quic_periyasa@quicinc.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>