Add missing cpu mem param to example/se.py.

configs/example/se.py:
    Add missing cpu mem param.

--HG--
extra : convert_revision : 29a11b09524612f079b8998e99b8f5ee8c67c8a6

configs/example/se.py

@@ -97,6 +97,7 @@ system = System(cpu = cpu,
                 membus = Bus())
 system.physmem.port = system.membus.port
 system.cpu.connectMemPorts(system.membus)
+system.cpu.mem = system.physmem
 
 root = Root(system = system)