Add an else clause that clears the return value.

This avoids several warnings with the GHS toolchain, in the form:
warning #111-D: statement is unreachable
This is because the sizeof() equality test is statically determined,
but the following code is not discarded automatically. It is when
using an explicit else clause.

Change-Id: Ic0584aafc72f70badcf5285ab635f9d99eac161a
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/tools/qstring.h

@@ -958,8 +958,9 @@ inline int QString::toWCharArray(wchar_t *array) const
     if (sizeof(wchar_t) == sizeof(QChar)) {
         memcpy(array, d->data(), sizeof(QChar) * size());
         return size();
+    } else {
+        return toUcs4_helper(d->data(), size(), reinterpret_cast<uint *>(array));
     }
-    return toUcs4_helper(d->data(), size(), reinterpret_cast<uint *>(array));
 }
 
 QT_WARNING_POP