ASoC: fix oops w/ for_each_rtd_codec_dai_rollback() macro

A kernel oops happens on an error case (usual missing BE mixer
configuration required by Intel SST driver). Git bisect points to this
macro and an operator precedence issue.

	for (; ((i--) >= 0) && ((dai) = rtd->codec_dais[i]);)

The initial code replaced by this macro was
	while (--i >= 0) {
		codec_dai = rtd->codec_dais[i];

Fix the C operator precedence difference by reverting to pre-decrement

Fixes: 0b7990e3

 ('ASoC: add for_each_rtd_codec_dai() macro')
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>