wifi: ath12k: fix a possible dead lock caused by ab->base_lock

wifi: ath12k: fix a possible dead lock caused by ab->base_lock

spin_lock/spin_unlock are used in ath12k_reg_chan_list_event
to acquire/release ab->base_lock. For now this is safe because
that function is only called in soft IRQ context.

But ath12k_reg_chan_list_event() will be called from process
context in an upcoming patch, and this can result in a deadlock
if ab->base_lock is acquired in process context and then soft
IRQ occurs on the same CPU and tries to acquire that lock.

Fix it by using spin_lock_bh and spin_unlock_bh instead.

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-v1-1-c869c86cad60@quicinc.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>