ASoC: SOF: IPC: reduce verbosity of IPC pointer updates

ASoC: SOF: IPC: reduce verbosity of IPC pointer updates

When using dynamic debug, the console is swamped with verbose position
pointer logs, which really don't add much information. Move then to
vdbg to keep traces usable and allow for easier end-user support.

Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200824200912.46852-6-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>