Correct use before definition bug in ARM

Author: theotherjimmy

tools/toolchains/arm.py

@@ -271,7 +271,7 @@ def link(self, output, objects, libraries, lib_dirs, scatter_file):
             new_scatter = self.correct_scatter_shebang(scatter_file)
             args.extend(["--scatter", new_scatter])
 
-        cmd_pre = self.ld + args
+        cmd = self.ld + args
 
         if self.RESPONSE_FILES:
             cmd_linker = cmd[0]