Change in flashrom[master]: dummyflasher: move struct declaration & probe_variable_size to spi.(h|c)

[Nico Huber (Code Review)]

Attention is currently required from: Namyoon Woo, Thomas Heijligen, Edward O'Callaghan, Anastasia Klimchuk.
Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/63831 )

Change subject: dummyflasher: move struct declaration & probe_variable_size to spi.(h|c)
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Patch Set 2:

(2 comments)

Patchset:

PS1:
> I have a question. I created https://ticket.coreboot. […]

We discussed this in a meeting today. I think the best is to
temporarily move the code as is into a separate file that re-
flects that there is more to do, e.g. `fixme.c`. Then this
patch can go in and Thomas doesn't have to wait for some-
body to fix the code.

File spi.c:

https://review.coreboot.org/c/flashrom/+/63831/comment/2ea3669e_39c783e4 
PS1, Line 133: int probe_variable_size(struct flashctx *flash)
             : {
             : 	unsigned int i;
             : 	const struct emu_data *emu_data = flash->mst->spi.data;
> Also it relies on emu_data, what happens if there is some other data in the context? another struct type?

You are spot-on, this is most likely undefined behavior. Probably what I had
in mind when I added this feature to the list of release-blocking issues. I
guess I commented about that on Gerrit a while ago (CB:44879). It's a perfect
example how merging without proper review and keeping broken code(!) affects
the project.