ASoC: wm9081: Remove #if IS_ENABLED(CONFIG_I2C)

wm9081 driver doesn't work without CONFIG_I2C anyway.
Let's remove #if IS_ENABLED(CONFIG_I2C)

And, this patch adds "depends on I2C" to Kconfig

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/Kconfig

@@ -1048,6 +1048,7 @@ config SND_SOC_WM8998
 
 config SND_SOC_WM9081
 	tristate
+	depends on I2C
 
 config SND_SOC_WM9090
 	tristate

sound/soc/codecs/wm9081.c

@@ -1304,7 +1304,6 @@ static const struct regmap_config wm9081_regmap = {
 	.cache_type = REGCACHE_RBTREE,
 };
 
-#if IS_ENABLED(CONFIG_I2C)
 static int wm9081_i2c_probe(struct i2c_client *i2c,
 			    const struct i2c_device_id *id)
 {
@@ -1384,7 +1383,6 @@ static struct i2c_driver wm9081_i2c_driver = {
 	.remove =   wm9081_i2c_remove,
 	.id_table = wm9081_i2c_id,
 };
-#endif
 
 module_i2c_driver(wm9081_i2c_driver);