ALSA: hda - Adjust speaker HPF and add LED support for HP Spectre 13

HP Spectre 13 has the IDT 92HD95 codec, and BIOS seems to set the
default high-pass filter in some "safer" range, which results in the
very soft tone from the built-in speakers in contrast to Windows.
Also, the mute LED control is missing, since 92HD95 codec still has no
HP-specific fixups for GPIO setups.

This patch adds these missing features: the HPF is adjusted by the
vendor-specific verb, and the LED is set up from a DMI string (but
with the default polarity = 0 assumption due to the incomplete BIOS on
the given machine).

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=74841
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Documentation/sound/alsa/HD-Audio-Models.txt

@@ -286,6 +286,11 @@ STAC92HD83*
   hp-inv-led	HP with broken BIOS for inverted mute LED
   auto		BIOS setup (default)
 
+STAC92HD95
+==========
+  hp-led	LED support for HP laptops
+  hp-bass	Bass HPF setup for HP Spectre 13
+
 STAC9872
 ========
   vaio		VAIO laptop without SPDIF