[MIPS] VR41xx: unsigned irq cannot be negative

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Acked-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/vr41xx/common/irq.c

@@ -72,15 +72,17 @@ static void irq_dispatch(unsigned int irq)
 	cascade = irq_cascade + irq;
 	if (cascade->get_irq != NULL) {
 		unsigned int source_irq = irq;
+		int ret;
 		desc = irq_desc + source_irq;
 		if (desc->chip->mask_ack)
 			desc->chip->mask_ack(source_irq);
 		else {
 			desc->chip->mask(source_irq);
 			desc->chip->ack(source_irq);
 		}
-		irq = cascade->get_irq(irq);
-		if (irq < 0)
+		ret = cascade->get_irq(irq);
+		irq = ret;
+		if (ret < 0)
 			atomic_inc(&irq_err_count);
 		else
 			irq_dispatch(irq);