auxdisplay: ks0108: initialize local parport variable

The local variable ks0108_parport is used by other functions to write to
the parallel port. We missed initializing it when we converted the
driver to use new Parallel Port codes.

Fixes: 4edd70c133 ("auxdisplay: ks0108: use new parport device model")
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/auxdisplay/ks0108.c

@@ -146,6 +146,7 @@ static void ks0108_parport_attach(struct parport *port)
 		goto err_unreg_device;
 	}
 
+	ks0108_parport = port;
 	ks0108_inited = 1;
 	return;
 
@@ -167,6 +168,7 @@ static void ks0108_parport_detach(struct parport *port)
 	parport_release(ks0108_pardevice);
 	parport_unregister_device(ks0108_pardevice);
 	ks0108_pardevice = NULL;
+	ks0108_parport = NULL;
 }
 
 /*