soundwire: add definition for maximum number of ports

A Device may have at most 15 physical ports (DP0, DP1..DP14).
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Link: https://lore.kernel.org/r/20200831134318.11443-3-yung-chuan.liao@linux.intel.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

include/linux/soundwire/sdw.h

@@ -38,7 +38,8 @@ struct sdw_slave;
 #define SDW_FRAME_CTRL_BITS		48
 #define SDW_MAX_DEVICES			11
 
-#define SDW_VALID_PORT_RANGE(n)		((n) <= 14 && (n) >= 1)
+#define SDW_MAX_PORTS			15
+#define SDW_VALID_PORT_RANGE(n)		((n) < SDW_MAX_PORTS && (n) >= 1)
 
 enum {
 	SDW_PORT_DIRN_SINK = 0,