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/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index 1cc5de1..01c1c16 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -633,13 +633,13 @@
 		return NULL;
 
 	if (i915_gem_object_get_pages(obj)) {
-		drm_gem_object_unreference(&obj->base);
+		i915_gem_object_put(obj);
 		return NULL;
 	}
 
 	if (i915_gem_obj_ggtt_pin(obj, PAGE_SIZE,
 			PIN_OFFSET_BIAS | GUC_WOPCM_TOP)) {
-		drm_gem_object_unreference(&obj->base);
+		i915_gem_object_put(obj);
 		return NULL;
 	}
 
@@ -661,7 +661,7 @@
 	if (i915_gem_obj_is_pinned(obj))
 		i915_gem_object_ggtt_unpin(obj);
 
-	drm_gem_object_unreference(&obj->base);
+	i915_gem_object_put(obj);
 }
 
 static void