[S] Change in coreboot[main]: {commonlib, libpayload}: Add "has_fw_splash_screen" entry

[Tim Van Patten (Code Review)]

Attention is currently required from: Andrey Petrov, Eric Lai, Kapil Porwal, Nick Vaccaro, Paz Zcharya, Subrata Banik.

Tim Van Patten has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/78388?usp=email )

Change subject: {commonlib, libpayload}: Add "has_fw_splash_screen" entry
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Patch Set 1:

(3 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/78388/comment/d4348fc1_ede6c50e :
PS1, Line 13: This information is useful for overriding the kernel command-line
            : argument fw_splash. If fw_splash=1, the kernel will skip modeset because
            : the splash screen has already been rendered by the firmware.
This is incorrect, because the kernel doesn't recognize or use `fw_splash`. Rather, it's a workaround to pass along the information to user space (`frecon`).

This CL should be blocked on the CrOS CL discussing how to use this information: https://crrev.com/c/4893558

https://review.coreboot.org/c/coreboot/+/78388/comment/18919993_814ec794 :
PS1, Line 18: fw_splash
`has_fw_splash_screen`

https://review.coreboot.org/c/coreboot/+/78388/comment/5baf6739_6c657609 :
PS1, Line 18: The payload (e.g., deptcharge) does not
            : have any other way to determine whether the firmware has initiated
            : screen rendering.
The payload doesn't actually care either though.