ASoC: SOF: trace: move to opt-in with Kconfig and module parameter

In a number of debug cases, the DMA-based trace can add problems
(e.g. with HDaudio channel allocation). It also generates additional
traffic on the bus and if the DMA handling is unreliable will prevent
audio use-cases from working normally. Using the trace also requires
tools to be installed on the target.

The trace can be instead handled as dynamic debug. We can use a
Kconfig to force the trace to be enabled in all cases, or use a module
parameter to enable it on a need-basis, e.g. by setting "options
snd_sof sof_debug=0x1" in a /etc/modprobe.d file.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20190927200538.660-4-pierre-louis.bossart@linux.intel.com


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