python: Enforce absolute imports for Python 3 compatibility

Change-Id: Ia88d7fd472f7aed9b97df81468211384981bf6c6
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/15983
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

src/python/m5/trace.py

@@ -26,5 +26,8 @@
 #
 # Authors: Nathan Binkert
 
+from __future__ import print_function
+from __future__ import absolute_import
+
 # Export native methods to Python
 from _m5.trace import output, ignore, disable, enable