mfd: ipaq-micro: Fix error check return value of platform_get_irq()

platform_get_irq() return negative value on failure, so null check of
irq is incorrect. Fix it by comparing whether it is less than zero.

Fixes: dcc21cc0 ("mfd: Add driver for Atmel Microcontroller on iPaq h3xxx")
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220412085305.2533030-1-lv.ruyi@zte.com.cn

drivers/mfd/ipaq-micro.c

@@ -403,7 +403,7 @@ static int __init micro_probe(struct platform_device *pdev)
 	micro_reset_comm(micro);
 
 	irq = platform_get_irq(pdev, 0);
-	if (!irq)
+	if (irq < 0)
 		return -EINVAL;
 	ret = devm_request_irq(&pdev->dev, irq, micro_serial_isr,
 			       IRQF_SHARED, "ipaq-micro",