ASoC: cs4341: fix waring unused-function

The driver cs4341 can be built with SPI and/or I2C, but it has to be one
of them at least. When I2C is set as a module we see the warning below:

sound/soc/codecs/cs4341.c:213:12: warning: ‘cs4341_probe’
defined but not used [-Wunused-function]
 static int cs4341_probe(struct device *dev)
            ^~~~~~~~~~~~

Rework so that we use IS_ENABLED instead of defined. Also change so
SND_SOC_CS4341 depends on SND_SOC_I2C_AND_SPI to we dont' get a link
error when SND_SOC_CS4341=y, I2C=m and REGMAP_I2C=m is set.
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/Kconfig

@@ -546,7 +546,7 @@ config SND_SOC_CS43130
 
 config SND_SOC_CS4341
 	tristate "Cirrus Logic CS4341 CODEC"
-	depends on I2C || SPI_MASTER
+	depends on SND_SOC_I2C_AND_SPI
 	select REGMAP_I2C if I2C
 	select REGMAP_SPI if SPI_MASTER
 

sound/soc/codecs/cs4341.c

@@ -223,7 +223,7 @@ static int cs4341_probe(struct device *dev)
 					       &cs4341_dai, 1);
 }
 
-#if defined(CONFIG_I2C)
+#if IS_ENABLED(CONFIG_I2C)
 static int cs4341_i2c_probe(struct i2c_client *i2c,
 			    const struct i2c_device_id *id)
 {
@@ -317,7 +317,7 @@ static int __init cs4341_init(void)
 {
 	int ret = 0;
 
-#if defined(CONFIG_I2C)
+#if IS_ENABLED(CONFIG_I2C)
 	ret = i2c_add_driver(&cs4341_i2c_driver);
 	if (ret)
 		return ret;
@@ -332,7 +332,7 @@ module_init(cs4341_init);
 
 static void __exit cs4341_exit(void)
 {
-#if defined(CONFIG_I2C)
+#if IS_ENABLED(CONFIG_I2C)
 	i2c_del_driver(&cs4341_i2c_driver);
 #endif
 #if defined(CONFIG_SPI_MASTER)