asoc: update curr_micbias2 val with mb->micb2_mv

Curr_micbias2 val should be same with mb->micba2_mv.
for some customers, their micbias is not 1800mv,
so we should set the curr_micbias as mb->micb2_mv which
was the actual micbias val the customer use.
remove the dev_up check from micbias, since with this check,
Headset may be detected as a incorrect type.

Change-Id: Ia5a1fd434a09617a57096531c69956479c69f079
Signed-off-by: Yuhui Zhao <quic_yuhuzhao@quicinc.com>

asoc/codecs/wcd9378/internal.h

@@ -138,7 +138,6 @@ struct wcd9378_priv {
 	struct snd_info_entry *version_entry;
 	struct snd_info_entry *variant_entry;
 	int flyback_cur_det_disable;
-	bool dev_up;
 	u8 tx_master_ch_map[WCD9378_MAX_SLAVE_CH_TYPES];
 	bool usbc_hs_status;
 	/* wcd to swr dmic notification */