ALSA: hda - Fix wrong model range check for ALC268

Fix a wrong value passed to snd_hda_check_board_codec_sid_config() as
the upper-limit in parse_alc268(), so that any wrong value can't be
passed.

So far, no bogus value was set in the quirk entries, so this won't give
any behavioral changes.

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