[S] Change in coreboot[main]: cpu/x86/64bit/mode_switch: Add workaround for FSP bug

[Maximilian Brune (Code Review)]

Attention is currently required from: Arthur Heymans, Jérémy Compostella, Patrick Rudolph.

Maximilian Brune has posted comments on this change by Patrick Rudolph. ( https://review.coreboot.org/c/coreboot/+/85789?usp=email )

Change subject: cpu/x86/64bit/mode_switch: Add workaround for FSP bug
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Patch Set 2: Code-Review+2

(1 comment)

File src/cpu/x86/64bit/mode_switch.S:

https://review.coreboot.org/c/coreboot/+/85789/comment/910ecd05_99d71d66?usp... :
PS2, Line 30: push	$0
            : 	push	$0
nit:
Could you use `pushq` to make it more obvious how much you push onto the stack? Since we are in both x86_32 and x86_64 in this file it would make it easier for me to see how much is being pushed at a glance.