ASoC: some minor changes for AD1836 and AD1938 codec drivers

1. delete redundant assignment to bus field in spi_driver structure
2. fix lost assignment to set_bias_level entry in ad1938 codec dai
3. change spi driver name of ad1836 from "ad1836-spi" to "ad1836"

Signed-off-by: Barry Song <barry.song@analog.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/codecs/ad1938.c

@@ -456,7 +456,6 @@ static int __devexit ad1938_spi_remove(struct spi_device *spi)
 static struct spi_driver ad1938_spi_driver = {
 	.driver = {
 		.name	= "ad1938",
-		.bus	= &spi_bus_type,
 		.owner	= THIS_MODULE,
 	},
 	.probe		= ad1938_spi_probe,
@@ -515,6 +514,7 @@ static int ad1938_register(struct ad1938_priv *ad1938)
 	codec->num_dai = 1;
 	codec->write = ad1938_write_reg;
 	codec->read = ad1938_read_reg_cache;
+	codec->set_bias_level = ad1938_set_bias_level;
 	INIT_LIST_HEAD(&codec->dapm_widgets);
 	INIT_LIST_HEAD(&codec->dapm_paths);