arm: mvebu: clearfog: adjust SCSI boot duplication

Fix duplication resulting from merging of multiple related series.
Commits cecf38a7, bd02fd29, and 201a500d added or adjusted SCSI
boot support for ClearFog, but in slightly different locations which
didn't result in a merge conflict.

Signed-off-by: Joel Johnson <mrjoel@lixil.net>
Reviewed-by: Stefan Roese <sr@denx.de>