soundwire: stream: extend sdw_alloc_stream() to take 'type' parameter

In the existing definition of sdw_stream_runtime, the 'type' member is
never set and defaults to PCM. To prepare for the BPT/BRA support, we
need to special-case streams and make use of the 'type'.

No functional change for now, the implicit PCM type is now explicit.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.dev>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Liam Girdwood <liam.r.girdwood@intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Tested-by:  <shumingf@realtek.com>
Link: https://lore.kernel.org/r/20250227140615.8147-5-yung-chuan.liao@linux.intel.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>