[PATCH] hostap: Fix null pointer dereference in prism2_pccard_card_present()

With my Buffalo WLI-CF-S11G PC Card kernel oopses every time in
prism2_interrupt() when I try load the hostap module. local->hw_priv is null
during the first call to prism2_interrupt(). It feels like
interrupts are enabled too early, or something.

This patch fixes the symptom, but not the cause.
Signed-off-by: Kalle Valo <Kalle.Valo@iki.fi>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

drivers/net/wireless/hostap/hostap_cs.c

@@ -212,7 +212,7 @@ static int prism2_event(event_t event, int priority,
 static int prism2_pccard_card_present(local_info_t *local)
 {
 	struct hostap_cs_priv *hw_priv = local->hw_priv;
-	if (hw_priv->link != NULL &&
+	if (hw_priv != NULL && hw_priv->link != NULL &&
 	    ((hw_priv->link->state & (DEV_PRESENT | DEV_CONFIG)) ==
 	     (DEV_PRESENT | DEV_CONFIG)))
 		return 1;