Get rid of lambda

Change-Id: Icf5cbef47e3822d43650ffd5ebe1baaa4e91f095
diff --git a/src/yang_schema.cpp b/src/yang_schema.cpp
index 3f562e1..266f917 100644
--- a/src/yang_schema.cpp
+++ b/src/yang_schema.cpp
@@ -457,10 +457,7 @@
         return libyang::Context::mod_missing_cb_return{LYS_IN_YANG, strdup(moduleSource.c_str())};
     };
 
-    auto deleter = [](void* data) {
-        free(data); // NOLINT(cppcoreguidelines-owning-memory,cppcoreguidelines-no-malloc)
-    };
-    m_context->add_missing_module_callback(lambda, deleter);
+    m_context->add_missing_module_callback(lambda, free);
 }
 
 std::shared_ptr<libyang::Data_Node> YangSchema::dataNodeFromPath(const std::string& path, const std::optional<const std::string> value) const