ALSA: hda/realtek - Fix inverted bass GPIO pin on Acer 8951G

We've added the bass speaker support on Acer 8951G by the commit
00066e97 ("Add Acer Aspire Ethos 8951G model quirk"), but it seems
that the GPIO pin was wrongly set: while the commit turns off the bit
to power up the amp, the actual hardware reacts other way round,
i.e. GPIO bit on = amp on.

So this patch fixes the bug, turning on the GPIO bit 0x02 as default.
Since turning on the GPIO bit can be more easily managed with
alc_setup_gpio() call, we simplify the quirk code by integrating the
GPIO setup into the existing alc662_fixup_aspire_ethos_hp() and
dropping the whole ALC669_FIXUP_ACER_ASPIRE_ETHOS_SUBWOOFER quirk.

Fixes: 00066e97

 ("Add Acer Aspire Ethos 8951G model quirk")
Reported-and-tested-by: Sergey 'Jin' Bostandzhyan <jin@mediatomb.cc>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191128202630.6626-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>