Improve sync packet handling

itm-decode.py

@@ -40,7 +40,7 @@ class ITMParser:
             # Resync
             if data == 0x00:
                 sync_count += 1
-            elif sync_count == 7 and data == 0x80:
+            elif sync_count >= 7 and data == 0x80:
                 raise ResyncException()
             else:
                 sync_count = 0
@@ -82,7 +82,7 @@ class ITMParser:
         """
 
         if c & 0x7f == 0:
-            return color("yellow", "sync")
+            return None # part of sync packet
 
         if c == 0x70:
             return color("yellow", "overflow")