ASoC: rt5645: add sys clk detection

Add system clock detection to prevent output DC from SPO.

Signed-off-by: Bard Liao <bardliao@realtek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/soc/codecs/rt5645.c b/sound/soc/codecs/rt5645.c
index 2813237..61bbeac 100644
--- a/sound/soc/codecs/rt5645.c
+++ b/sound/soc/codecs/rt5645.c
@@ -1646,9 +1646,13 @@
 			RT5645_PWR_CLS_D_L,
 			RT5645_PWR_CLS_D | RT5645_PWR_CLS_D_R |
 			RT5645_PWR_CLS_D_L);
+		snd_soc_update_bits(codec, RT5645_GEN_CTRL3,
+			RT5645_DET_CLK_MASK, RT5645_DET_CLK_MODE1);
 		break;
 
 	case SND_SOC_DAPM_PRE_PMD:
+		snd_soc_update_bits(codec, RT5645_GEN_CTRL3,
+			RT5645_DET_CLK_MASK, RT5645_DET_CLK_DIS);
 		snd_soc_write(codec, RT5645_EQ_CTRL2, 0);
 		snd_soc_update_bits(codec, RT5645_PWR_DIG1,
 			RT5645_PWR_CLS_D | RT5645_PWR_CLS_D_R |