ASoC: samsung: tm2_wm5110: check of of_parse return value

cppcheck warning:

sound/soc/samsung/tm2_wm5110.c:605:6: style: Variable 'ret' is
reassigned a value before the old one has been
used. [redundantAssignment]
 ret = devm_snd_soc_register_component(dev, &tm2_component,
     ^
sound/soc/samsung/tm2_wm5110.c:554:7: note: ret is assigned
  ret = of_parse_phandle_with_args(dev->of_node, "i2s-controller",
      ^
sound/soc/samsung/tm2_wm5110.c:605:6: note: ret is overwritten
 ret = devm_snd_soc_register_component(dev, &tm2_component,
     ^

The args is a stack variable, so it could have junk (uninitialized)
therefore args.np could have a non-NULL and random value even though
property was missing. Later could trigger invalid pointer dereference.

There's no need to check for args.np because args.np won't be
initialized on errors.

Fixes: 8d1513ce ("ASoC: samsung: Add support for HDMI audio on TM2 board")
Cc: <stable@vger.kernel.org>
Suggested-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210312180231.2741-2-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/samsung/tm2_wm5110.c

@@ -553,7 +553,7 @@ static int tm2_probe(struct platform_device *pdev)
 
 		ret = of_parse_phandle_with_args(dev->of_node, "i2s-controller",
 						 cells_name, i, &args);
-		if (!args.np) {
+		if (ret) {
 			dev_err(dev, "i2s-controller property parse error: %d\n", i);
 			ret = -EINVAL;
 			goto dai_node_put;