drm/i915/chv: Bump num_pipes to 3

CHV has three pipes so let's expose them all.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Antti Koskipää <antti.koskipaa@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -345,7 +345,7 @@ static const struct intel_device_info intel_broadwell_gt3m_info = {
 
 static const struct intel_device_info intel_cherryview_info = {
 	.is_preliminary = 1,
-	.gen = 8, .num_pipes = 2,
+	.gen = 8, .num_pipes = 3,
 	.need_gfx_hws = 1, .has_hotplug = 1,
 	.ring_mask = RENDER_RING | BSD_RING | BLT_RING | VEBOX_RING,
 	.is_valleyview = 1,