ASoC: intel: fix the kernldoc comment

copypaste error on function sst_get_num_channel caused the comment to be
wrong, so fix it here

Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/sst/sst_drv_interface.c

@@ -94,7 +94,7 @@ int sst_get_sfreq(struct snd_sst_params *str_param)
 }
 
 /*
- * sst_get_sfreq - this function returns the frequency of the stream
+ * sst_get_num_channel - get number of channels for the stream
  *
  * @str_param : stream params
  */