phy: phy-sun4i-usb: Fix optional gpios failing probe

The interrupt 0 is not a valid interrupt number. In the event where the
retrieval of the vbus-det gpio would return null, the gpiod_to_irq
callback would return 0, while the current code makes the assumption
that it is a valid interrupt, and would go on calling request_irq.
Obviously, this would fail, preventing the driver from probing properly,
while the vbus and id gpios are optional.
Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

drivers/phy/phy-sun4i-usb.c

@@ -645,11 +645,11 @@ static int sun4i_usb_phy_probe(struct platform_device *pdev)
 
 	data->id_det_irq = gpiod_to_irq(data->id_det_gpio);
 	data->vbus_det_irq = gpiod_to_irq(data->vbus_det_gpio);
-	if ((data->id_det_gpio && data->id_det_irq < 0) ||
-	    (data->vbus_det_gpio && data->vbus_det_irq < 0))
+	if ((data->id_det_gpio && data->id_det_irq <= 0) ||
+	    (data->vbus_det_gpio && data->vbus_det_irq <= 0))
 		data->phy0_poll = true;
 
-	if (data->id_det_irq >= 0) {
+	if (data->id_det_irq > 0) {
 		ret = devm_request_irq(dev, data->id_det_irq,
 				sun4i_usb_phy0_id_vbus_det_irq,
 				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
@@ -660,7 +660,7 @@ static int sun4i_usb_phy_probe(struct platform_device *pdev)
 		}
 	}
 
-	if (data->vbus_det_irq >= 0) {
+	if (data->vbus_det_irq > 0) {
 		ret = devm_request_irq(dev, data->vbus_det_irq,
 				sun4i_usb_phy0_id_vbus_det_irq,
 				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,