Change in flashrom[master]: flashrom: Convert do_read() into a libflashrom user

[Nico Huber (Code Review)]

Attention is currently required from: Edward O'Callaghan, Angel Pons, Daniel Campello, Anastasia Klimchuk.
Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/59291 )

Change subject: flashrom: Convert do_read() into a libflashrom user
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Patch Set 6:

(1 comment)

File cli_classic.c:

https://review.coreboot.org/c/flashrom/+/59291/comment/7fca2f0f_8765753e 
PS4, Line 635: 			if (map_flash(&flashes[0]) != 0) {
             : 				free(flashes[0].chip);
             : 				ret = 1;
             : 				goto out_shutdown;
             : 			}
             : 			msg_cinfo("Please note that forced reads most likely contain garbage.\n");
             : 			ret = do_read(&flashes[0], filename);
             : 			unmap_flash(&flashes[0]);
> That is a good point, I removed them. Luckily force should by-pass the safety checks called from prepare_flash_access() WDYT?

I would just put it into its own commit for now. If you want to refactor
this CLI code that's not a bad idea, I stumbled over this path myself many
times. But it seems rather orthogonal to the do_it() conversion.

Also, the forced-read path should be easy to test, e.g. put a PWM signal
on MISO and try to read that. Or start by testing it without any signal
at all, to see if the control path still works.