control: JSON parsing compile framework

Add the enabling framework of use of JSON config files for fan control.

Tested:
    Compile passes when `--enable-json` configure flag given
    Compile passes without enabling JSON
    No functional change when not using JSON

Change-Id: Ic70bfc63ad74cb79559ed839784cd214df403cb2
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
diff --git a/control/json_parser.hpp b/control/json_parser.hpp
new file mode 100644
index 0000000..eea2564
--- /dev/null
+++ b/control/json_parser.hpp
@@ -0,0 +1,19 @@
+/**
+ * Copyright © 2020 IBM Corporation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#pragma once
+
+namespace phosphor::fan::control
+{} // namespace phosphor::fan::control