ALSA: soc-compress: add support to snd_compr_set_runtime_buffer()

Existing compress offload code allocates data buffers using simple kmalloc,
however there are situations where these buffers have to be mapped
in smmu. So provide a way to set the runtime buffer by the driver itself,
simillar to what we do with pcm.

This patch adds support to set runtime dma buffer on compressed stream.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>