ASoC: SOF: Add `memory_info` file to debugfs

This file content describes memory allocation status
at run-time, typically to detect memory leaks.

Signed-off-by: Karol Trzcinski <karolx.trzcinski@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20201124180017.2232128-5-kai.vehmanen@linux.intel.com


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