[coreboot] [PATCH 4/6 V3] Geode GX2 cleanup patch

[Nils]

Remove duplicated GX2 processor IIOC mode setting on CS5535 southbridge code
and fix CIS mode comments.

Signed-off-by: Nils Jacobs

V2: Add a extra comment.
V3: Remove already commited part.

Thanks, Nils.