drm/i915: Convert i915_semaphores_is_enabled over to early sanitize

Rather than recomputing whether semaphores are enabled, we can do that
computation once during early initialisation as the i915.semaphores
module parameter is now read-only.

s/i915_semaphores_is_enabled/i915.semaphores/

v2: Add the state to the debug dmesg as well

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1469005202-9659-10-git-send-email-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1469017917-15134-9-git-send-email-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 618f8cf..9aa62c5 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -3220,7 +3220,7 @@
 	enum intel_engine_id id;
 	int j, ret;
 
-	if (!i915_semaphore_is_enabled(dev_priv)) {
+	if (!i915.semaphores) {
 		seq_puts(m, "Semaphores are disabled\n");
 		return 0;
 	}