ASoC: fsl_sai: initialize is_dsp_mode flag

ASoC: fsl_sai: initialize is_dsp_mode flag

Initialize is_dsp_mode flag in the beginning of function
fsl_sai_set_dai_fmt_tr().

When the DAIFMT is DAIFMT_DSP_B the first time, is_dsp_mode is
true, then the second time DAIFMT is DAIFMT_I2S, is_dsp_mode
still true, which is a wrong state. So need to initialize
is_dsp_mode flag every time.

Fixes: a3f7dcc9cc03 ("ASoC: fsl-sai: Add SND_SOC_DAIFMT_DSP_A/B support.")
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Reviewed-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Link: https://lore.kernel.org/r/1673852874-32200-1-git-send-email-shengjiu.wang@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>