ALSA: core: Expand DMA buffer information

Update DMA buffer definition for snd_compr_runtime so it is represented
similarly as in snd_pcm_runtime. While at it, modify
snd_compr_set_runtime_buffer to account for newly added members.

Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Vinod Koul <vkoul@kernel.org>
Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200218143924.10565-2-cezary.rojewski@intel.com


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