[S] Change in flashrom[master]: meson: Add support for ni845x_spi on Windows

[Peter Marheine (Code Review)]

Attention is currently required from: Miklós Márton, Thomas Heijligen.

Peter Marheine has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/75236?usp=email )

Change subject: meson: Add support for ni845x_spi on Windows
......................................................................

Patch Set 6: Code-Review+1

(3 comments)

Commit Message:

https://review.coreboot.org/c/flashrom/+/75236/comment/d37ec5d8_9be0c8b7 :
PS4, Line 10:      meson setup -Dprogrammer=ni845x build
> meson setup -Dprogrammer=ni845x_spi build

Done

Patchset:

PS4:
> I have cherry picked this commit: […]

I rebased this branch on top of master (currently b09aad573) and it built successfully for me.

```
MINGW32$ meson setup -Dprogrammer=ni845x_spi build
MINGW32$ meson compile -C build
MINGW32$ ./build/flashrom.exe
flashrom 1.4.0-devel (git:v1.2-1302-g7ba095dd) on Windows 10.0 (x86)
flashrom is free software, get the source code at https://flashrom.org

Using clock_gettime for delay loops (clk_id: 1, resolution: 100ns).
Please select a programmer with the --programmer parameter.
Valid choices are:
ni845x_spi.
```

I've gone ahead and updated this set of changes by rebasing, since Gerrit required it to fix some merge conflicts anyway.

File ni845x_spi.c:

https://review.coreboot.org/c/flashrom/+/75236/comment/90e5975f_aa753489 :
PS4, Line 19:  * Define it just here, since this driver will only work on 32-bit Windows.
> I've to dig deeper into this macro to figure out when it's set from the compiler. […]

Acknowledged