ASoC: SOF: pcm: remove unnecessary function declaration

ASoC: SOF: pcm: remove unnecessary function declaration

sof_pcm_setup_connected_widgets() can be a static function in pcm.c. No
need to declare it in the header.

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://lore.kernel.org/r/20220426171743.171061-9-ranjani.sridharan@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>