ALSA: hda - update documentation for no-primary-hp fixup

The problem addressed by this fixup is not specific to Vaio Z, affecting
some Vaio all-in-one desktop PCs too. Update the code comments accordingly.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>