wifi: ath12k: fix dfs-radar and temperature event locking

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: wifi: ath12k: fix dfs-radar and temperature event locking The ath12k active pdevs are protected by RCU but the DFS-radar and temperature event handling code calling ath12k_mac_get_ar_by_pdev_id() was not marked as a read-side critical section. Mark the code in question as RCU read-side critical sections to avoid any potential use-after-free issues. Note that the temperature event handler looks like a place holder currently but would still trigger an RCU lockdep splat. Compile tested only.

References

• https://git.kernel.org/stable/c/774de37c147fea81f2c2e4be5082304f4f71d535
• https://git.kernel.org/stable/c/d7a5f7f76568e48869916d769e28b9f3ca70c78e
• https://git.kernel.org/stable/c/69bd216e049349886405b1c87a55dce3d35d1ba7