[submodule] Update submodule sonic-linux-kernel to the latest HEAD automatically (sonic-net#21860)

#### Why I did it
src/sonic-linux-kernel
```
* 7faad28 - (HEAD -> master, origin/master, origin/HEAD) Revert "[optoe] Reset page select byte to 0 before upper memory access on pag…" (sonic-net#467) (5 days ago) [Prince George]
```
#### How I did it
#### How to verify it
#### Description for the changelog

Author: mssonicbld