spi: fsl-spi: Do not check 0 for platform_get_irq()

Since platform_get_irq() never returned zero, so it need not to check
whether it returned zero, and we use the return error code of
platform_get_irq() to replace the current return error code, for that
platform_get_irq() may return -EINVAL or -ENXIO.
Signed-off-by: Zhu Wang <wangzhu9@huawei.com>
Link: https://lore.kernel.org/r/20230803083944.21501-1-wangzhu9@huawei.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-fsl-spi.c

@@ -740,8 +740,8 @@ static int plat_mpc8xxx_spi_probe(struct platform_device *pdev)
 		return -EINVAL;
 
 	irq = platform_get_irq(pdev, 0);
-	if (irq <= 0)
-		return -EINVAL;
+	if (irq < 0)
+		return irq;
 
 	master = fsl_spi_probe(&pdev->dev, mem, irq);
 	return PTR_ERR_OR_ZERO(master);