doc: kernel: fix obj param in doxygen comment

Use same argument name for doxygen.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/include/kernel.h b/include/kernel.h
index d52a7b3..3327bb8 100644
--- a/include/kernel.h
+++ b/include/kernel.h
@@ -199,7 +199,7 @@
  * Intended to be called as the last statement in kernel object init
  * functions.
  *
- * @param object Address of the kernel object
+ * @param obj Address of the kernel object
  */
 void _k_object_init(void *obj);
 #else