[L] Change in flashrom[master]: flashrom_tester: Rewrite IOOpts to support more operations

[Peter Marheine (Code Review)]

Attention is currently required from: Evan Benn.

Peter Marheine has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/71973 )

Change subject: flashrom_tester: Rewrite IOOpts to support more operations
......................................................................

Patch Set 4:

(2 comments)

File util/flashrom_tester/flashrom/src/cmd.rs:

https://review.coreboot.org/c/flashrom/+/71973/comment/525e8598_96929efd 
PS4, Line 82:     // an operation must provide a file or a region.file or both.
Does this vary with what operation is being performed? It might be more obvious (regarding correct use of fields) to make each `Operation` have fields for the relevant options:

```
enum LayoutSource {
    Fmap,
    LayoutFile(Path),
}

enum Region {
    EntireChip,
    Named(&str, LayoutSource),
}

enum Operation {
    Read(Region, Path),
    Write(Region, Path),
    ...
    Erase(Region),
}
```

https://review.coreboot.org/c/flashrom/+/71973/comment/2ad73be2_293b7e40 
PS4, Line 148:     #[allow(clippy::needless_update)] // clippy doesnt like Default when all fields are filled
Seems okay to omit the `default` then, unless you anticipate adding more fields that would require adding it back in.