ASoC: rt5514-spi: Fix potential NULL pointer dereference

There is a potential NULL pointer dereference in case devm_kzalloc()
fails and returns NULL.

Fix this by adding a NULL check on rt5514_dsp.

This issue was detected with the help of Coccinelle.

Fixes: 6eebf35b ("ASoC: rt5514: add rt5514 SPI driver")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/rt5514-spi.c

@@ -280,6 +280,8 @@ static int rt5514_spi_pcm_probe(struct snd_soc_component *component)
 
 	rt5514_dsp = devm_kzalloc(component->dev, sizeof(*rt5514_dsp),
 			GFP_KERNEL);
+	if (!rt5514_dsp)
+		return -ENOMEM;
 
 	rt5514_dsp->dev = &rt5514_spi->dev;
 	mutex_init(&rt5514_dsp->dma_lock);