ALSA: compress_offload: introduce accel operation mode

There is a requirement to expose the audio hardware that accelerates various
tasks for user space such as sample rate converters, compressed
stream decoders, etc.

This is description for the API extension for the compress ALSA API which
is able to handle "tasks" that are not bound to real-time operations
and allows for the serialization of operations.

For details, refer to "compress-accel.rst" document.

Cc: Mark Brown <broonie@kernel.org>
Cc: Shengjiu Wang <shengjiu.wang@gmail.com>
Cc: Nicolas Dufresne <nicolas@ndufresne.ca>
Cc: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Cc: Pierre-Louis Bossart <pierre-louis.bossart@linux.dev>
Cc: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Reviewed-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Tested-by: Shengjiu Wang <shengjiu.wang@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20241002093904.1809799-1-perex@perex.cz