pcmcia: check for pointer instead of pointer address

Bug noted by Michael Buesch: checking for the pointer address is always true.
This didn't matter much, for the very first check in pcmcia_release_window()
was for the pointer pointing to something, and the return value is ignored
here. Nonetheless, fix it.

CC: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

drivers/pcmcia/pcmcia_resource.c

@@ -966,7 +966,7 @@ void pcmcia_disable_device(struct pcmcia_device *p_dev) {
 	pcmcia_release_configuration(p_dev);
 	pcmcia_release_io(p_dev, &p_dev->io);
 	pcmcia_release_irq(p_dev, &p_dev->irq);
-	if (&p_dev->win)
+	if (p_dev->win)
 		pcmcia_release_window(p_dev->win);
 }
 EXPORT_SYMBOL(pcmcia_disable_device);