spi: bcm63xx-hsspi: checking for ERR_PTR instead of NULL

devm_request_and_ioremap() returns NULL on error, it doesn't return an
ERR_PTR().  This patch fixes it by switching to devm_ioremap_resource()
which is the prefered function anyway.

Fixes: 142168eba9dc ('spi: bcm63xx-hsspi: add bcm63xx HSSPI driver')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Jonas Gorski <jogo@openwrt.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/spi/spi-bcm63xx-hsspi.c

@@ -338,7 +338,7 @@ static int bcm63xx_hsspi_probe(struct platform_device *pdev)
 	}
 
 	res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	regs = devm_request_and_ioremap(dev, res_mem);
+	regs = devm_ioremap_resource(dev, res_mem);
 	if (IS_ERR(regs))
 		return PTR_ERR(regs);