intel_idle: disable Atom/Lincroft HW C-state auto-demotion

Just as we had to disable auto-demotion for NHM/WSM,
we need to do the same for Atom (Lincroft version).

In particular, auto-demotion will prevent Lincroft
from entering the S0i3 idle power saving state.

https://bugzilla.kernel.org/show_bug.cgi?id=25252

Signed-off-by: Len Brown <len.brown@intel.com>