config: Fix ommission of number base in ethernet address param

The ethernet address param tries to convert a hexadecimal
string using int() in python, which defaults to base 10,
need to specify base 16 in this case.

src/python/m5/params.py

@@ -697,7 +697,7 @@ class EthernetAddr(ParamValue):
             raise TypeError, 'invalid ethernet address %s' % value
 
         for byte in bytes:
-            if not 0 <= int(byte) <= 0xff:
+            if not 0 <= int(byte, base=16) <= 0xff:
                 raise TypeError, 'invalid ethernet address %s' % value
 
         self.value = value