ASoC: sirf-audio-codec: Fix return value check in sirf_audio_codec_driver_probe()

In case of error, the function devm_ioremap_resource() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check should
be replaced with IS_ERR().
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/codecs/sirf-audio-codec.c

@@ -471,8 +471,8 @@ static int sirf_audio_codec_driver_probe(struct platform_device *pdev)
 
 	mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	base = devm_ioremap_resource(&pdev->dev, mem_res);
-	if (base == NULL)
-		return -ENOMEM;
+	if (IS_ERR(base))
+		return PTR_ERR(base);
 
 	sirf_audio_codec->regmap = devm_regmap_init_mmio(&pdev->dev, base,
 					    &sirf_audio_codec_regmap_config);