ALSA: hda - VIA: Update VT1708 initial verbs

Add a verb of power down jack detect in VT1708 initial verbs.
This verb is used to avoid noise caused by hardware issue.

Signed-off-by: Lydia Wang <lydiawang@viatech.com.cn>
Signed-off-by: Takashi Iwai <tiwai@suse.de>