spi: xilinx: Handle errors from platform_get_irq()

The Xilinx SPI driver can operate without an IRQ, but not every error
returned by platform_get_irq() means that no IRQ was specified. It will
also return an error if the IRQ specification is invalid or the IRQ
provider is not yet available (EPROBE_DEFER).

So instead of ignoring all errors only ignore ENXIO, which means no IRQ was
specified, and propagate all other errors to device driver core.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-xilinx.c

@@ -455,7 +455,10 @@ static int xilinx_spi_probe(struct platform_device *pdev)
 	xspi->buffer_size = xilinx_spi_find_buffer_size(xspi);
 
 	xspi->irq = platform_get_irq(pdev, 0);
-	if (xspi->irq >= 0) {
+	if (xspi->irq < 0 && xspi->irq != -ENXIO) {
+		ret = xspi->irq;
+		goto put_master;
+	} else if (xspi->irq >= 0) {
 		/* Register for SPI Interrupt */
 		ret = devm_request_irq(&pdev->dev, xspi->irq, xilinx_spi_irq, 0,
 				dev_name(&pdev->dev), xspi);