Allocate the sof_ipc4_fw_data struct for IPC4 and set the fw header offset
for the platforms which will be used by the core when loading the firmware
image.

The core expects that the "private" field in struct snd_sof_dev (which is
unused today with IPC3) is used to save this data.
Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20220511171648.1622993-6-ranjani.sridharan@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>