Fix platforms for QtSerialBus

There are several Windows CAN plugins available,
and Modbus can be used usable on Windows also.

Change-Id: Ia5fb2561db4f0b97547ec7ed4fe4ed48ebb8e283
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

doc/src/qtmodules.qdoc

@@ -278,8 +278,8 @@
         \li Provides access to sensor hardware and motion gesture recognition.
     \row
         \li \l[QtSerialBus]{Qt Serial Bus}
-        \li \l{Qt for Linux/X11}{Linux}
-        \li \l{Qt for Linux/X11}{Linux} and \l{Boot2Qt}{Boot to Qt} targets.
+        \li All
+        \li \l{Qt for Windows}{Windows}, \l{Qt for Linux/X11}{Linux} and \l{Boot2Qt}{Boot to Qt} targets.
         \li Provides access to serial industrial bus interface. Currently the
             module supports the CAN bus and Modbus protocols.
     \row