Changed LPC11U35 online toolchain to uARM

Added the ONLINE_TOOLCHAIN tag to the LPC11U35_401 target class in order
to prevent ARM Standard from being used instead of ARM Micro.

workspace_tools/targets.py

@@ -363,6 +363,8 @@ class LPC11C24(Target):
 
 
 class LPC11U35_401(Target):
+    ONLINE_TOOLCHAIN = "uARM"
+
     def __init__(self):
         Target.__init__(self)