ALSA: hda: Update documentation for aliasing via the model option

The previous patch allowed user to specify the aliasing of SSID via
model option for applying a quirk.  Update the documentation
accordingly.

Link: https://lore.kernel.org/r/20210823073722.14873-4-tiwai@suse.de


Signed-off-by: Takashi Iwai <tiwai@suse.de>