drm/i915: Rename drm_gem_object_unreference in preparation for lockless free

Ultimately wraps kref_put(), so adopt its nomenclature for consistency
with other subsystems.

s/drm_gem_object_unreference/i915_gem_object_put/

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1469005202-9659-6-git-send-email-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1469017917-15134-5-git-send-email-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 6282fca..439aeab 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1367,7 +1367,7 @@
 	if (ret) {
 		DRM_DEBUG_DRIVER("pin LRC WA ctx backing obj failed: %d\n",
 				 ret);
-		drm_gem_object_unreference(&engine->wa_ctx.obj->base);
+		i915_gem_object_put(engine->wa_ctx.obj);
 		return ret;
 	}
 
@@ -1378,7 +1378,7 @@
 {
 	if (engine->wa_ctx.obj) {
 		i915_gem_object_ggtt_unpin(engine->wa_ctx.obj);
-		drm_gem_object_unreference(&engine->wa_ctx.obj->base);
+		i915_gem_object_put(engine->wa_ctx.obj);
 		engine->wa_ctx.obj = NULL;
 	}
 }
@@ -2382,7 +2382,7 @@
 error_ringbuf:
 	intel_ringbuffer_free(ringbuf);
 error_deref_obj:
-	drm_gem_object_unreference(&ctx_obj->base);
+	i915_gem_object_put(ctx_obj);
 	ce->ringbuf = NULL;
 	ce->state = NULL;
 	return ret;