drm/i915: don't flood the logs about bdw semaphores

BDW is no longer flagged as preliminary hw, but without
i915.preliminary_hw_support module param set the logs are filled with
WARNs about it.

Just make semaphores off the BDW per-chip default for now.

CC: Ben Widawsky <ben@bwidawsk.net>
Reported-by: NSebastien Dufour <sebastien.dufour@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -403,15 +403,13 @@ bool i915_semaphore_is_enabled(struct drm_device *dev)
 	if (INTEL_INFO(dev)->gen < 6)
 		return false;
 
-	/* Until we get further testing... */
-	if (IS_GEN8(dev)) {
-		WARN_ON(!i915.preliminary_hw_support);
-		return false;
-	}
-
 	if (i915.semaphores >= 0)
 		return i915.semaphores;
 
+	/* Until we get further testing... */
+	if (IS_GEN8(dev))
+		return false;
+
 #ifdef CONFIG_INTEL_IOMMU
 	/* Enable semaphores on SNB when IO remapping is off */
 	if (INTEL_INFO(dev)->gen == 6 && intel_iommu_gfx_mapped)