spi: lp-8841: return correct error code from probe

The spi_lp8841_rtc_probe() function misses an initialization of the
return code when it fails to get its memory resource, as gcc notices:

drivers/spi/spi-lp8841-rtc.c: In function 'spi_lp8841_rtc_probe':
drivers/spi/spi-lp8841-rtc.c:239:9: error: 'ret' may be used uninitialized in this function [-Werror=maybe-uninitialized]

This changes the code to propagate the error from devm_ioremap_resource().

Fixes: 7ecbfff6711f ("spi: master driver to enable RTC on ICPDAS LP-8841")
Signed-off-by: Arnd Bergmann <[e-mail]>
Tested-by: Sergei Ianovich <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

drivers/spi/spi-lp8841-rtc.c

···
 	data = spi_master_get_devdata(master);
 
 	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	data->iomem =  devm_ioremap_resource(&pdev->dev, iomem);
-	if (IS_ERR(data->iomem)) {
+	data->iomem = devm_ioremap_resource(&pdev->dev, iomem);
+	ret = PTR_ERR_OR_ZERO(data->iomem);
+	if (ret) {
 		dev_err(&pdev->dev, "failed to get IO address\n");
 		goto err_put_master;
 	}