ALSA: hda/realtek: Enable mute LED on HP EliteBook 840 G6

ALSA: hda/realtek: Enable mute LED on HP EliteBook 840 G6

The HP EliteBook 840 G6 (PCI SSID 103c:854d) has an ALC215 codec whose
mic-mute and audio-mute LEDs are wired to the same GPIOs as the already
supported EliteBook 830 G6 and 840 G7. Without a matching quirk the LEDs
are never registered, so the front-panel mic-mute LED stays permanently
lit and does not track the mute state.

Apply ALC285_FIXUP_HP_GPIO_LED, mirroring the sibling EliteBook entries.
With this fixup the codec registers an "hda::micmute" LED class device and
the LED correctly follows the capture-mute state. This was verified on the
affected machine by forcing the same fixup at runtime via
snd_sof_intel_hda_generic.hda_model=103c:8548, which made the LED work as
expected.

Signed-off-by: Ramcharan Rajpurohit <b23ci1032@iitj.ac.in>
Link: https://patch.msgid.link/20260619062435.26256-1-b23ci1032@iitj.ac.in
Signed-off-by: Takashi Iwai <tiwai@suse.de>