ALSA: hda - Disable Headphone Mic boost for ALC662

When headphone mic boost is above zero, some 10 - 20 second delay
might occur before the headphone mic is operational.
Therefore disable the headphone mic boost control (recording gain is
sufficient even without it).

(Note: this patch is not about the headset mic, it's about the less
common mic-in only mode.)

BugLink: https://bugs.launchpad.net/bugs/1454235


Suggested-by: Kailang Yang <kailang@realtek.com>
Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>