drm/i915: properly init lockdep class

The code has an ifdef and uses two functions to either init the bare
spinlock or init it and set a lock-class. It is possible to do the same
thing without an ifdef.
With this patch (in debug case) we first use the "default" lock class
which is later overwritten to the supplied one. Without lockdep the set
name/class function vanishes.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171214131009.7479-1-joonas.lahtinen@linux.intel.comSigned-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

drivers/gpu/drm/i915/i915_gem_timeline.c

@@ -33,11 +33,8 @@ static void __intel_timeline_init(struct intel_timeline *tl,
 {
 	tl->fence_context = context;
 	tl->common = parent;
-#ifdef CONFIG_DEBUG_SPINLOCK
-	__raw_spin_lock_init(&tl->lock.rlock, lockname, lockclass);
-#else
 	spin_lock_init(&tl->lock);
-#endif
+	lockdep_set_class_and_name(&tl->lock, lockclass, lockname);
 	init_request_active(&tl->last_request, NULL);
 	INIT_LIST_HEAD(&tl->requests);
 	i915_syncmap_init(&tl->sync);