samples: i2s_codec: Remove duplicate configurations

Remove duplicate configurations.

Signed-off-by: Zhaoxiang Jin <Zhaoxiang.Jin_1@nxp.com>
diff --git a/samples/drivers/i2s/i2s_codec/boards/frdm_mcxn236.conf b/samples/drivers/i2s/i2s_codec/boards/frdm_mcxn236.conf
index 444b842b..1b143f4 100644
--- a/samples/drivers/i2s/i2s_codec/boards/frdm_mcxn236.conf
+++ b/samples/drivers/i2s/i2s_codec/boards/frdm_mcxn236.conf
@@ -7,7 +7,6 @@
 CONFIG_SAMPLE_FREQ=16000
 CONFIG_I2S_INIT_BUFFERS=1
 CONFIG_USE_CODEC_CLOCK=y
-CONFIG_USE_DMIC=n
 CONFIG_USE_DMIC=y
 CONFIG_DMIC_CHANNELS=1
 CONFIG_EXTRA_BLOCKS=10