configs: Fix Python 3 iterator and exec compatibility issues

Python 2.7 used to return lists for operations such as map and range,
this has changed in Python 3. To make the configs Python 3 compliant,
add explicit conversions from iterators to lists where needed, replace
xrange with range, and fix changes to exec syntax.

This change doesn't fix import paths since that might require us to
restructure the configs slightly.

Change-Id: Idcea8482b286779fc98b4e144ca8f54069c08024
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/16002
Reviewed-by: Gabe Black <gabeblack@google.com>

configs/dram/lat_mem_rd.py

@@ -188,7 +188,7 @@ def create_trace(filename, max_addr, burst_size, itt):
     protolib.encodeMessage(proto_out, header)
 
     # create a list of every single address to touch
-    addrs = range(0, max_addr, burst_size)
+    addrs = list(range(0, max_addr, burst_size))
 
     import random
     random.shuffle(addrs)

configs/dram/low_power_sweep.py

@@ -166,11 +166,11 @@ pd_entry_time = (system.mem_ctrls[0].tRAS.value +
 
 # We sweep itt max using the multipliers specified by the user.
 itt_max_str = args.itt_list.strip().split()
-itt_max_multiples = map(lambda x : int(x), itt_max_str)
+itt_max_multiples = [ int(x) for x in itt_max_str ]
 if len(itt_max_multiples) == 0:
     fatal("String for itt-max-list detected empty\n")
 
-itt_max_values = map(lambda m : pd_entry_time * m, itt_max_multiples)
+itt_max_values = [ pd_entry_time * m for m in itt_max_multiples ]
 
 # Generate request addresses in the entire range, assume we start at 0
 max_addr = mem_range.end