ASoC: Intel: sst: Remove 2 unused members from stream_info struct

Remove the unused ops and str_id members from the stream_info struct.

While at it also remove some kernel-doc comments for members which have
already been removed in the past.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mark Brown <broonie@kernel.org>