util/superiotool: Add initial support for Exar XR28V384.

Datasheet
https://www.exar.com/content/document.ashx?id=21368

Add support for Exar chip used on a custom board
that was designed to connect to the Olive Hill Plus
development platform. The register dump was verified
on the Olive Hill Plus platform.

Change-Id: Ibd3e13eefb706bd99b6e5b38634f6855b39848ab
Signed-off-by: Derek Waldner <derek.waldner.os@gmail.com>
Reviewed-on: https://review.coreboot.org/14367
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
3 files changed