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

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/isurf.c

@@ -238,7 +238,7 @@ int setup_isurf(struct IsdnCard *card)
 				cs->hw.isurf.reset = pnp_port_start(pnp_d, 0);
 				cs->hw.isurf.phymem = pnp_mem_start(pnp_d, 1);
 				cs->irq = pnp_irq(pnp_d, 0);
-				if (!cs->irq || !cs->hw.isurf.reset || !cs->hw.isurf.phymem) {
+				if (cs->irq == -1 || !cs->hw.isurf.reset || !cs->hw.isurf.phymem) {
 					printk(KERN_ERR "ISurfPnP:some resources are missing %d/%x/%lx\n",
 					       cs->irq, cs->hw.isurf.reset, cs->hw.isurf.phymem);
 					pnp_disable_dev(pnp_d);