ASoC: SOF: ipc4: Define platform dependent library loading callback

Platforms where external libraries can be supported should set the
load_library callback to implement this functionality.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Chao Song <chao.song@intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20221020121238.18339-14-peter.ujfalusi@linux.intel.com


Signed-off-by: Mark Brown <broonie@kernel.org>