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>