drm/i915/kbl: Remove preliminary_hw_support protection from KBL.

We now have KBL machines running in our CI systems and with no
blocking issues that could cause a full hangs or blank screens.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1459349881-951-1-git-send-email-rodrigo.vivi@intel.com
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -360,14 +360,12 @@ static const struct intel_device_info intel_broxton_info = {
 
 static const struct intel_device_info intel_kabylake_info = {
 	BDW_FEATURES,
-	.is_preliminary = 1,
 	.is_kabylake = 1,
 	.gen = 9,
 };
 
 static const struct intel_device_info intel_kabylake_gt3_info = {
 	BDW_FEATURES,
-	.is_preliminary = 1,
 	.is_kabylake = 1,
 	.gen = 9,
 	.ring_mask = RENDER_RING | BSD_RING | BLT_RING | VEBOX_RING | BSD2_RING,