extcon: max77693: fix handling return value of regmap_irq_get_virq

The function can return negative values, so its result should
be assigned to signed variable.

Signed-off-by: Andrzej Hajda <[e-mail]>
Suggested-by: Krzysztof Kozlowski <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Chanwoo Choi <[e-mail]>

drivers/extcon/extcon-max77693.c

···
 	/* Support irq domain for MAX77693 MUIC device */
 	for (i = 0; i < ARRAY_SIZE(muic_irqs); i++) {
 		struct max77693_muic_irq *muic_irq = &muic_irqs[i];
-		unsigned int virq = 0;
+		int virq;
 
 		virq = regmap_irq_get_virq(max77693->irq_data_muic,
 					muic_irq->irq);
-		if (!virq)
+		if (virq <= 0)
 			return -EINVAL;
 		muic_irq->virq = virq;