ASoC: SOF: expose sof_route_setup()

This will be used in IPC3-specific code.

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20220317175044.1752400-18-ranjani.sridharan@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>