drm/i915/breadcrumbs: s/container_of/rb_entry/

In keeping with commit f802cf7e ("drm/i915/debugfs: use
rb_entry()"), convert the primary user of the rbtrees over to using
rb_entry rather than the equivalent container_of.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20161220104003.8044-1-chris@chris-wilson.co.ukReviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_breadcrumbs.c

@@ -154,7 +154,7 @@ static void __intel_breadcrumbs_disable_irq(struct intel_breadcrumbs *b)
 
 static inline struct intel_wait *to_wait(struct rb_node *node)
 {
-	return container_of(node, struct intel_wait, node);
+	return rb_entry(node, struct intel_wait, node);
 }
 
 static inline void __intel_breadcrumbs_finish(struct intel_breadcrumbs *b,
@@ -427,7 +427,7 @@ static bool signal_complete(struct drm_i915_gem_request *request)
 
 static struct drm_i915_gem_request *to_signaler(struct rb_node *rb)
 {
-	return container_of(rb, struct drm_i915_gem_request, signaling.node);
+	return rb_entry(rb, struct drm_i915_gem_request, signaling.node);
 }
 
 static void signaler_set_rtpriority(void)