ASoC: SOF: Intel: MTL: remove the unnecessary snd_sof_dsp_read()

The return val of snd_sof_dsp_read() right before polling the same
register is not used, so remove the redundant call.

Signed-off-by: Yong Zhi <yong.zhi@intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20220922213644.666315-11-ranjani.sridharan@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>