drm/i915/cfl: Coffee Lake reuses Kabylake DMC.

both platforms. We haven't recieved any separated release
specifically for Coffee Lake so let's just re-use what
is already there for Kabylake.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1497038550-30910-1-git-send-email-rodrigo.vivi@intel.com