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

The devm_ioremap() function returns NULL on error, it doesn't return
error pointers.  Fix the check to match.

Fixes: 79b8a70 ("spi: stm32: Add OSPI driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Link: https://patch.msgid.link/bc4c9123-df43-4616-962f-765801d30b4c@stanley.mountain
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: Dan Carpenter

drivers/spi/spi-stm32-ospi.c

@@ -835,10 +835,10 @@ static int stm32_ospi_get_resources(struct platform_device *pdev)
 	if (rmem) {
 		ospi->mm_size = rmem->size;
 		ospi->mm_base = devm_ioremap(dev, rmem->base, rmem->size);
-		if (IS_ERR(ospi->mm_base)) {
+		if (!ospi->mm_base) {
 			dev_err(dev, "unable to map memory region: %pa+%pa\n",
 				&rmem->base, &rmem->size);
-			ret = PTR_ERR(ospi->mm_base);
+			ret = -ENOMEM;
 			goto err_dma;
 		}