px_uploader: fix typo and Python 3 issue

Tools/px_uploader.py

@@ -333,8 +333,8 @@ class uploader(object):
         length = self.__recv_int()
         value = self.__recv(length)
         self.__getSync()
-        peices = value.split(",")
-        return peices
+        pieces = value.split(b",")
+        return pieces
 
     def __drawProgressBar(self, label, progress, maxVal):
         if maxVal < progress: