ASoC: SOF: ipc3-dtrace: Add helper function to update the sdev->host_offset

ASoC: SOF: ipc3-dtrace: Add helper function to update the sdev->host_offset

We are using the READ_ONCE() on the debugfs read path for accessing
sdev->host_offset, but the set is not atomic or protected in any way.

Add a small helper to do the host_offset update and be really paranoid
about the a possible race in update

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20220610080119.30880-3-peter.ujfalusi@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>