Increase DIAL buffer size to allow 4kB content and url

Change-Id: Ia72ccfed92f4df1a0737a01ee7c63aa66aab41fd
diff --git a/src/server/dial_server.h b/src/server/dial_server.h
index 1558aa2..37b160c 100644
--- a/src/server/dial_server.h
+++ b/src/server/dial_server.h
@@ -44,7 +44,8 @@
 /*
  * The maximum DIAL payload accepted per the DIAL 1.6.1 specification.
  */
-#define DIAL_MAX_PAYLOAD (4096)
+/* Increased size in 1.7 to allow 256 bytes of additional data */
+#define DIAL_MAX_PAYLOAD (4352)
 
 /*
  * Cast service data