Make commenting on close namespace brackets consistent.

Ran all the source files through 'perl -pi' with this script:

s|\s*(};?\s*)?/\*\s*(end\s*)?namespace\s*(\S+)\s*\*/(\s*})?|} // namespace $3|;
s|\s*};?\s*//\s*(end\s*)?namespace\s*(\S+)\s*|} // namespace $2\n|;
s|\s*};?\s*//\s*(\S+)\s*namespace\s*|} // namespace $1\n|;

Also did a little manual editing on some of the arch/*/isa_traits.hh files
and src/SConscript.

src/python/m5/params.py

@@ -1004,7 +1004,7 @@ namespace Enums {
         code.dedent(2)
         code('''
     };
-/* namespace Enums */ }
+} // namespace Enums
 ''')
 
 # Base class for enum types.