x86: Add Geos profile for Geode subtarget

This makes the Geode images actually useful again. The Geos profile
should include the relevant hardware for that board, and the Default
profile adds the via-rhine adapter which seems to have been present in
the net5501 and alix targets killed in commit 9e0759ea ("x86: merge
all geode based subtargets into one").

Signed-off-by: David Woodhouse <dwmw2@infradead.org>