pata-rb532-cf: platform_get_irq() fix ignored failure

platform_get_irq() can return -ENXIO, but since 'irq' is an
unsigned int, it does not show when the IRQ resource wasn't found.
Make irq an int so that we can use a single variable to test the
platform_get_irq() return value.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Phil Sutter <n0-1@freewrt.org>
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/pata_rb532_cf.c

@@ -104,7 +104,7 @@ static void rb532_pata_setup_ports(struct ata_host *ah)
 
 static __devinit int rb532_pata_driver_probe(struct platform_device *pdev)
 {
-	unsigned int irq;
+	int irq;
 	int gpio;
 	struct resource *res;
 	struct ata_host *ah;