soundwire: intel: fix PDI/stream mapping for Bulk

soundwire: intel: fix PDI/stream mapping for Bulk

[ Upstream commit c134f914e9f55b7817e2bae625ec0e5f1379f7cd ]

The previous formula is incorrect for PDI0/1, the mapping is not
linear but has a discontinuity between PDI1 and PDI2.

This change has no effect on PCM PDIs (same mapping).

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20191022232948.17156-1-pierre-louis.bossart@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>