soundwire: fix the kernel-doc comment

sdw_startup_stream() and sdw_shutdown_stream() argument has been updated
but not the comments, so update these as well to fix warning with W=1

drivers/soundwire/stream.c:1859: warning: Function parameter or member 'sdw_substream' not described in 'sdw_startup_stream'
drivers/soundwire/stream.c:1859: warning: Excess function parameter 'stream' description in 'sdw_startup_stream'
drivers/soundwire/stream.c:1903: warning: Function parameter or member 'sdw_substream' not described in 'sdw_shutdown_stream'
drivers/soundwire/stream.c:1903: warning: Excess function parameter 'stream' description in 'sdw_shutdown_stream'

Signed-off-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200715095702.1519554-1-vkoul@kernel.org


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