drm/i915: Wrap drm_gem_object_reference in i915_gem_object_get

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

s/drm_gem_object_reference/i915_gem_object_get/

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1469005202-9659-5-git-send-email-chris@chris-wilson.co.uk
Reviewed-by: Dave Gordon <david.s.gordon@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1469017917-15134-4-git-send-email-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c
index 6f10b42..3aa76d3 100644
--- a/drivers/gpu/drm/i915/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c
@@ -190,7 +190,7 @@
 			if (!can_release_pages(obj))
 				continue;
 
-			drm_gem_object_reference(&obj->base);
+			i915_gem_object_get(obj);
 
 			/* For the unbound phase, this should be a no-op! */
 			list_for_each_entry_safe(vma, v,