[submodule] Update submodule sonic-linux-kernel to the latest HEAD au…

…tomatically (#16759)

#### Why I did it
src/sonic-linux-kernel
```
* d5232ab - (HEAD -> master, origin/master, origin/HEAD) arm64: ac5: Fix watchdog timeleft (#334) (7 days ago) [pavannaregundi]
```
#### How I did it
#### How to verify it
#### Description for the changelog