drm/i915: there is no pipe CxSR on ironlake

After checking the specs and discussing with Jesse, turns out CxSR is not
available on Ironlake and gen5, and its advertisement on the device
description is misleading.
Acked-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -198,7 +198,7 @@ static const struct intel_device_info intel_pineview_info = {
 
 static const struct intel_device_info intel_ironlake_d_info = {
 	.gen = 5,
-	.need_gfx_hws = 1, .has_pipe_cxsr = 1, .has_hotplug = 1,
+	.need_gfx_hws = 1, .has_hotplug = 1,
 	.has_bsd_ring = 1,
 };