formatQEnum: deal with enum class types

The enum class doesn't get treated as an int automatically, the
way that a plain enum does; so there's a silly compile error which
this cast fixes.

Change-Id: I21b56337e4f724e4de1819e22bc93e9af23c51ea
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/io/qdebug_p.h

@@ -93,7 +93,7 @@ static inline void formatQEnum(QDebug &debug, QEnum value)
 {
     const QMetaObject *metaObject = qt_getEnumMetaObject(value);
     const QMetaEnum me = metaObject->enumerator(metaObject->indexOfEnumerator(qt_getEnumName(value)));
-    if (const char *key = me.valueToKey(value))
+    if (const char *key = me.valueToKey(int(value)))
         debug << key;
     else
         debug << int(value);