phy: renesas: rcar-gen3-usb2: exit if request_irq() failed

To avoid unexpected behaviors, it's better to exit if request_irq()
failed.

Suggested-by: Vinod Koul <[e-mail]>
Signed-off-by: Yoshihiro Shimoda <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/phy/renesas/phy-rcar-gen3-usb2.c

···
 		INIT_WORK(&channel->work, rcar_gen3_phy_usb2_work);
 		ret = request_irq(channel->irq, rcar_gen3_phy_usb2_irq,
 				  IRQF_SHARED, dev_name(channel->dev), channel);
-		if (ret < 0)
+		if (ret < 0) {
 			dev_err(channel->dev, "No irq handler (%d)\n", channel->irq);
+			return ret;
+		}
 	}
 
 	/* Initialize USB2 part */