Audmix support two substream, When two substream start
to run, the trigger function may be called by two substream
in same time, that the priv->tdms may be updated wrongly.

The expected priv->tdms is 0x3, but sometimes the
result is 0x2, or 0x1.

Fixes: be1df61c ("ASoC: fsl: Add Audio Mixer CPU DAI driver")
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
Link: https://lore.kernel.org/r/1e706afe53fdd1fbbbc79277c48a98f8416ba873.1573458378.git.shengjiu.wang@nxp.comSigned-off-by: Mark Brown <broonie@kernel.org>
Cc: <stable@vger.kernel.org>