Schannel: remove outdated comment

It is clearly not temporary anymore, nor is the reference to
qsslsocket_winrt useful.

Change-Id: If746959ddaf8ee564a62b4d168306c79aa466026
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

src/plugins/tls/schannel/qtls_schannel.cpp

@@ -139,7 +139,6 @@ QList<QSslCipher> defaultCiphers()
 {
     // Previously the code was in QSslSocketBackendPrivate.
     QList<QSslCipher> ciphers;
-    // @temp (I hope), stolen from qsslsocket_winrt.cpp
     const QString protocolStrings[] = { QStringLiteral("TLSv1"), QStringLiteral("TLSv1.1"),
                                         QStringLiteral("TLSv1.2"), QStringLiteral("TLSv1.3") };
 QT_WARNING_PUSH