Add a patch for printing the AMD Zen CPU reset reason

If I intentionally trigger a CPU soft reset I see this:
```
admin@gold208-dut:~$ sudo dmesg | grep -i reason
[    0.635233] x86/amd: Previous system reset reason [0x00080800]: software wrote 0x6 to reset control register 0xCF9
```

If I intentionally trigger the CPU FCH Watchdog, I see this:
```
admin@gold208-dut:~$ sudo dmesg | grep reason
[    0.632563] x86/amd: Previous system reset reason [0x02000800]: hardware watchdog timer expired
```

Upstream from here:

https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=ab8131028710d009ab93d6bffd2a2749ade909b0

The patch had to be adapted to v6.1 we're using, that was basically
adding the entire contents (5 constants) of `fch.h` as the file didn't
exist in v6.1, and updating the patch for `amd.c` for context.

Signed-off-by: Nate White <[email protected]>

Author: lotus-nexthop