meson: switch config.h to config.hpp

Enable a transition of this file from C to C++ so that we
can use C++ constants instead of #defines in future commits.

Change-Id: I1149ebdaaeb99b7e7974ca846b9b07a3399edea0
Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@wiwynn.com>
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/inc/power_button_profile.hpp b/inc/power_button_profile.hpp
index 37bfbe6..bb113a3 100644
--- a/inc/power_button_profile.hpp
+++ b/inc/power_button_profile.hpp
@@ -1,6 +1,6 @@
 #pragma once
 
-#include "config.h"
+#include "config.hpp"
 
 #include <sdbusplus/bus.hpp>
 #include <sdbusplus/bus/match.hpp>