drm/i915: Rename request reference/unreference to get/put

Now that we derive requests from struct fence, swap over to its
nomenclature for references. It's shorter and more idiomatic across the
kernel.

s/i915_gem_request_reference/i915_gem_request_get/
s/i915_gem_request_unreference/i915_gem_request_put/

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1469005202-9659-2-git-send-email-chris@chris-wilson.co.uk
Link: http://patchwork.freedesktop.org/patch/msgid/1469017917-15134-1-git-send-email-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 51fbca7..2f7af85 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -10954,11 +10954,10 @@
 	mutex_lock(&dev->struct_mutex);
 	intel_unpin_fb_obj(work->old_fb, primary->state->rotation);
 	drm_gem_object_unreference(&work->pending_flip_obj->base);
-
-	if (work->flip_queued_req)
-		i915_gem_request_assign(&work->flip_queued_req, NULL);
 	mutex_unlock(&dev->struct_mutex);
 
+	i915_gem_request_put(work->flip_queued_req);
+
 	intel_frontbuffer_flip_complete(dev, to_intel_plane(primary)->frontbuffer_bit);
 	intel_fbc_post_update(crtc);
 	drm_framebuffer_unreference(work->old_fb);