Change in coreboot[master]: lib/cbfs: Add cbfs_preload()

[Raul Rangel (Code Review)]

Attention is currently required from: Jason Glenesk, Furquan Shaikh, Marshall Dawson, Julius Werner, Karthik Ramasubramanian, Felix Held.
Raul Rangel has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/56491 )

Change subject: lib/cbfs: Add cbfs_preload()
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Patch Set 12:

(2 comments)

File src/lib/Kconfig:

https://review.coreboot.org/c/coreboot/+/56491/comment/d8a3de8b_566350f1 
PS7, Line 108: config CBFS_PRELOAD
> Well, it shouldn't really make a practical difference if the controller uses PIO, it'll just not giv […]

Right, it doesn't cause an actual problem booting. It just means that the async transactions can turn into sync transactions unexpectedly and thus penalizing a random section of code.

File src/lib/cbfs.c:

https://review.coreboot.org/c/coreboot/+/56491/comment/777d4c4e_a0b6a309 
PS11, Line 511: 		cbfs_unmap(rdev_mmap_full(&rdev));
> Rather than duplicating everything in the error path I think it would be better to just merge them,  […]

Done