wifi: ath11k: fix htt pktlog locking

In the Linux kernel, the following vulnerability has been resolved: wifi: ath11k: fix htt pktlog locking The ath11k active pdevs are protected by RCU but the htt pktlog handling code calling ath11k_mac_get_ar_by_pdev_id() was not marked as a read-side critical section. Mark the code in question as an RCU read-side critical section to avoid any potential use-after-free issues. Compile tested only.