ALSA: hda - Add chained_before flag to the fixup entry

Sometimes we want to call a fixup after applying other existing
fixups, but currently the fixup chain mechanism allows only the call
the others after the target fixup.  This patch adds a new flag,
chained_before, to struct hda_fixup, for allowing the chained call
before the current execution.

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