drm/i915: enable ring freq scaling, RC6 and graphics turbo on Ivy Bridge v3

drm/i915: enable ring freq scaling, RC6 and graphics turbo on Ivy Bridge v3

commit 1c70c0cebd1295a42fec75045b8a6b4419cedef3 upstream.

They use the same register interfaces, so we can simply enable the
existing code on IVB.

v2:
  - resolve conflict with ring freq scaling, we can enable it too
v3:
  - resolve conflict again, this time on drm-intel-next

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Robert Hooker <robert.hooker@canonical.com>
Acked-by: Leann Ogasawara <leann.ogasawara@canonical.com>
Acked-by: Herton Krzesinski <herton.krzesinski@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>