ALSA: hda: intel-nhlt: Correct the handling of fmt_config flexible array

The struct nhlt_format's fmt_config is a flexible array, it must not be
used as normal array.
When moving to the next nhlt_fmt_cfg we need to take into account the data
behind the ->config.caps (indicated by ->config.size).

Fixes: a864e8f1 ("ALSA: hda: intel-nhlt: verify config type")
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Jaska Uimonen <jaska.uimonen@linux.intel.com>
Link: https://lore.kernel.org/r/20220823122405.18464-1-peter.ujfalusi@linux.intel.com


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