ASoC: codecs: pcm186x: fix wrong usage of DECLARE_TLV_DB_SCALE()

According to DS, the gain is between -12 dB and 40 dB, with a 0.5 dB step.
Tested on pcm1863.
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Acked-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

sound/soc/codecs/pcm186x.c

@@ -42,7 +42,7 @@ struct pcm186x_priv {
 	bool is_master_mode;
 };
 
-static const DECLARE_TLV_DB_SCALE(pcm186x_pga_tlv, -1200, 4000, 50);
+static const DECLARE_TLV_DB_SCALE(pcm186x_pga_tlv, -1200, 50, 0);
 
 static const struct snd_kcontrol_new pcm1863_snd_controls[] = {
 	SOC_DOUBLE_R_S_TLV("ADC Capture Volume", PCM186X_PGA_VAL_CH1_L,