x86/early quirk: use gen6 stolen detection for VLV

x86/early quirk: use gen6 stolen detection for VLV

commit 7bd40c16ccb2cb6877dd00b0e66249c171e6fa43 upstream.

We've always been able to use either method on VLV, but it appears more
recent BIOSes only support the gen6 method, so switch over to that.

References: https://bugs.freedesktop.org/show_bug.cgi?id=71370
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>