ASoC: samsung: idma: Check of ioremap return value

Because of the potential failure of the ioremap(), the buf->area could
be NULL.
Therefore, we need to check it and return -ENOMEM in order to transfer
the error.

Fixes: f09aecd5 ("ASoC: SAMSUNG: Add I2S0 internal dma driver")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20211228034026.1659385-1-jiasheng@iscas.ac.cnSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/samsung/idma.c

@@ -360,6 +360,8 @@ static int preallocate_idma_buffer(struct snd_pcm *pcm, int stream)
 	buf->addr = idma.lp_tx_addr;
 	buf->bytes = idma_hardware.buffer_bytes_max;
 	buf->area = (unsigned char * __force)ioremap(buf->addr, buf->bytes);
+	if (!buf->area)
+		return -ENOMEM;
 
 	return 0;
 }