ASoC: SOF: loader: Remove the old fw_ready related code

The fw_ready is handled internally to ipc3, we can remove the old code
from the loader.c along with the functions only used by the fw_ready()

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Ajit Pandey <ajitkumar.pandey@amd.com>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
Link: https://lore.kernel.org/r/20220421080735.31698-7-peter.ujfalusi@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>