ASoC: rt5659: remove redundant assignment to variable idx

Variable idx is being assigned with a value that is never idx, it is
assigned a new value a couple of statements later. The assignment is
redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20200208221529.37105-1-colin.king@canonical.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/rt5659.c

@@ -1604,7 +1604,7 @@ static int set_dmic_clk(struct snd_soc_dapm_widget *w,
 {
 	struct snd_soc_component *component = snd_soc_dapm_to_component(w->dapm);
 	struct rt5659_priv *rt5659 = snd_soc_component_get_drvdata(component);
-	int pd, idx = -EINVAL;
+	int pd, idx;
 
 	pd = rl6231_get_pre_div(rt5659->regmap,
 		RT5659_ADDA_CLK_1, RT5659_I2S_PD1_SFT);