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/util/smartdict.py

@@ -41,9 +41,11 @@
 # rather than a normal value, and (c) coerce values written to the
 # dict to be strings.
 
+from __future__ import print_function
+from __future__ import absolute_import
 
-from convert import *
-from attrdict import attrdict
+from .convert import *
+from .attrdict import attrdict
 
 class Variable(str):
     """Intelligent proxy class for SmartDict.  Variable will use the