ASoC: tegra: Fix a NULL vs IS_ERR() check

The tegra_machine_parse_phandle() function doesn't return NULL, it returns
error pointers.

Fixes: cc8f70f5 ("ASoC: tegra: Unify ASoC machine drivers")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/YMyjOKFsPe9SietU@mwandaSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/tegra/tegra_asoc_machine.c

@@ -409,7 +409,7 @@ int tegra_asoc_machine_probe(struct platform_device *pdev)
 		return PTR_ERR(np_codec);
 
 	np_i2s = tegra_machine_parse_phandle(dev, "nvidia,i2s-controller");
-	if (!np_i2s)
+	if (IS_ERR(np_i2s))
 		return PTR_ERR(np_i2s);
 
 	card->dai_link->cpus->of_node = np_i2s;