isdn: hisax: Fix pnp_irq's error checking for setup_sedlbauer_isapnp

The pnp_irq() function returns -1 if an error occurs.
pnp_irq() error checking for zero is not correct.
Signed-off-by: NArvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/isdn/hisax/sedlbauer.c

@@ -558,7 +558,7 @@ static int setup_sedlbauer_isapnp(struct IsdnCard *card, int *bytecnt)
 				card->para[1] = pnp_port_start(pnp_d, 0);
 				card->para[0] = pnp_irq(pnp_d, 0);
 
-				if (!card->para[0] || !card->para[1]) {
+				if (card->para[0] == -1 || !card->para[1]) {
 					printk(KERN_ERR "Sedlbauer PnP:some resources are missing %ld/%lx\n",
 					       card->para[0], card->para[1]);
 					pnp_disable_dev(pnp_d);