ALSA: HDA VIA: Replace buggy Mic Boost

VT1708S' Mic Boost should be hidden in hardware design according to some
customers' requirements.  However, in case of bugs, it has to be exhibited to
normal users, so we need to:
* open a software backdoor, which is disabled by default in hardware
* re-write .tlv & .info, to indicate the actual necessary info, which we cannot
  get from amplifier's capabiliies

Signed-off-by: Logan Li <LoganLi@viatech.com.cn>
Signed-off-by: Harald Welte <HaraldWelte@viatech.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>