[coreboot-gerrit] Change in coreboot[master]: libpayload: Add boot_device_read() function

[Julius Werner (Code Review)]

Attention is currently required from: Jakub Czapiga.
Julius Werner has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/59492 )

Change subject: libpayload: Add boot_device_read() function
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Patch Set 6: Code-Review+2

(1 comment)

Commit Message:

https://review.coreboot.org/c/coreboot/+/59492/comment/f2146b53_6976a1f0 
PS6, Line 12: This patch also provides a fallback implementation
            : of this function using cbfs_media, but it will be removed in the future
            : together with cbfs_media API.
nit: outdated