soundwire: add definition for DPn BlockPackingMode

For some reason we don't have an enum for this concept. Add
definitions following Table 102 of the SoundWire 1.2 specification.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20210323050701.23760-2-yung-chuan.liao@linux.intel.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

include/linux/soundwire/sdw.h

@@ -125,6 +125,12 @@ enum sdw_dpn_grouping {
 	SDW_BLK_GRP_CNT_4 = 3,
 };
 
+/* block packing mode enum */
+enum sdw_dpn_pkg_mode {
+	SDW_BLK_PKG_PER_PORT = 0,
+	SDW_BLK_PKG_PER_CHANNEL = 1
+};
+
 /**
  * enum sdw_stream_type: data stream type
  *