ALSA: hda/realtek: Add quirks for ASUS GU604V and GU603V

These models use 2 CS35L41 amplifiers using SPI for down-facing
speakers.

alc285_fixup_speaker2_to_dac1 is needed to fix volume control of the
down-facing speakers.

Pin configs are needed to enable headset mic detection.

Note that these models lack the ACPI _DSD properties needed to
initialize the amplifiers. They can be added during boot to get working
sound out of the speakers:
  https://gist.github.com/lamperez/862763881c0e1c812392b5574727f6ff

Signed-off-by: Alexandru Sorodoc <ealex95@gmail.com>
Link: https://lore.kernel.org/r/20230511161510.315170-1-ealex95@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>