Add check for supported modes.
Add check for supported modes.

Throw on unsupported modes.
Set correct deciders and platform for our internal modes.

Change-Id: Id3f23227da68044fe70e9fe791e543753eef9ef4
Signed-off-by: Steve Sylvester <b0839a0405c3f908ea9b10b668e5564aefda5af5@intel.com>

cmcantalupo/geopm,sssylvester/geopm,geopm/geopm,cmcantalupo/geopm,geopm/geopm,geopm/geopm,cmcantalupo/geopm,geopm/geopm,sssylvester/geopm,sssylvester/geopm,sssylvester/geopm,geopm/geopm,cmcantalupo/geopm,cmcantalupo/geopm