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_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 47f244f..163d28e 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2306,6 +2306,17 @@
 extern struct drm_gem_object *
 drm_gem_object_lookup(struct drm_file *file, u32 handle);
 
+__attribute__((nonnull))
+static inline struct drm_i915_gem_object *
+i915_gem_object_get(struct drm_i915_gem_object *obj)
+{
+	drm_gem_object_reference(&obj->base);
+	return obj;
+}
+
+__deprecated
+extern void drm_gem_object_reference(struct drm_gem_object *);
+
 static inline bool
 i915_gem_object_has_struct_page(const struct drm_i915_gem_object *obj)
 {