soundwire: update Intel BPT message length limitation

The limitation of "must be multiples of 32 bytes" does not fit the
requirement of current Intel platforms. Update it to meet the
requirement.

Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>

Author: bardliao

Documentation/driver-api/soundwire/bra.rst

@@ -333,4 +333,4 @@ FIFO sizes to avoid xruns.
 
 Alignment requirements are currently not enforced at the core level
 but at the platform-level, e.g. for Intel the data sizes must be
-multiples of 32 bytes.
+equal to or larger than 16 bytes.

drivers/soundwire/intel_ace2x.c

@@ -245,17 +245,17 @@ static void intel_ace2x_bpt_close_stream(struct sdw_intel *sdw, struct sdw_slave
 	cdns->bus.bpt_stream = NULL;
 }
 
-#define INTEL_BPT_MSG_BYTE_ALIGNMENT 32
+#define INTEL_BPT_MSG_BYTE_MIN 16
 
 static int intel_ace2x_bpt_send_async(struct sdw_intel *sdw, struct sdw_slave *slave,
 				      struct sdw_bpt_msg *msg)
 {
 	struct sdw_cdns *cdns = &sdw->cdns;
 	int ret;
 
-	if (msg->len % INTEL_BPT_MSG_BYTE_ALIGNMENT) {
-		dev_err(cdns->dev, "BPT message length %d is not a multiple of %d bytes\n",
-			msg->len, INTEL_BPT_MSG_BYTE_ALIGNMENT);
+	if (msg->len < INTEL_BPT_MSG_BYTE_MIN) {
+		dev_err(cdns->dev, "BPT message length %d is less than the minimum bytes %d\n",
+			msg->len, INTEL_BPT_MSG_BYTE_MIN);
 		return -EINVAL;
 	}