Fix unused variables error

Enforcing werror=true in meson would by default convert all
the warnings into error, there by fixing unused variables is
necessary.

Signed-off-by: Manojkiran Eda <manojkiran.eda@gmail.com>
Change-Id: I3ffd7b3a5e876ff306dd4f05343360c30fd7e6d3
diff --git a/inc/post_code.hpp b/inc/post_code.hpp
index 7ae515f..98af300 100644
--- a/inc/post_code.hpp
+++ b/inc/post_code.hpp
@@ -91,7 +91,7 @@
     PostCodeDataHolder *postcodeDataHolderObj =
         postcodeDataHolderObj->getInstance();
 
-    PostCode(sdbusplus::bus::bus &bus, const char *path, EventPtr &event) :
+    PostCode(sdbusplus::bus::bus &bus, const char *path, EventPtr & /*event*/) :
         sdbusplus::server::object_t<post_code, delete_all>(bus, path), bus(bus),
         propertiesChangedSignalRaw(
             bus,