spi: stm32-ospi: Fix NULL vs IS_ERR() bug in stm32_ospi_get_resources()

This code was changed from using devm_ioremap() which returns NULL to
using devm_ioremap_resource() which returns error pointers.  Update
the error checking to match.

Fixes: defe01a ("spi: stm32-ospi: Use of_reserved_mem_region_to_resource() for "memory-region"")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://patch.msgid.link/fb2a26a2-119b-4b5a-8d44-b29e2c736081@sabinyo.mountain
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: Dan Carpenter

drivers/spi/spi-stm32-ospi.c

@@ -823,9 +823,9 @@ static int stm32_ospi_get_resources(struct platform_device *pdev)
 	if (!ret) {
 		ospi->mm_size = resource_size(res);
 		ospi->mm_base = devm_ioremap_resource(dev, res);
-		if (!ospi->mm_base) {
+		if (IS_ERR(ospi->mm_base)) {
 			dev_err(dev, "unable to map memory region: %pR\n", res);
-			ret = -ENOMEM;
+			ret = PTR_ERR(ospi->mm_base);
 			goto err_dma;
 		}