[coreboot-gerrit] Change in coreboot[master]: mb/asus/p2b{,-ls}: Get rid of power button device

[Keith Hui (Code Review)]

Keith Hui has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/40007 )

Change subject: mb/asus/p2b{,-ls}: Get rid of power button device
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Patch Set 2: Code-Review-1

I propose we add a a config option HAVE_ACPI_POWER_BUTTON which then changes the flag in generated FADT for all southbridges. This will need extensive boot testing though.