[coreboot-gerrit] Change in coreboot[master]: drivers/ocp/ipmi: Add ipmi POST start/end command

[Jonathan Zhang (Code Review)]

Jonathan Zhang has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/41605 )

Change subject: drivers/ocp/ipmi: Add ipmi POST start/end command
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Patch Set 4: -Code-Review

With this design, POST start/end IPMI commands are sent during ramstage, when the IPMI_OCP device is initialized and finalized.

Ideally the behavior should be similar to traditional firmware,I think:
* POST start IPMI command should be sent as early as possible, in romstage when IPMI communication is established.
* POST end IPMI command should be sent as late as possible, either in ramstage just before control is given to payload, or in Linuxboot uinit just before control is given to target OS.