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.
diff --git a/src/arch/arm/isa_traits.hh b/src/arch/arm/isa_traits.hh
index a24852b..b2989e4 100644
--- a/src/arch/arm/isa_traits.hh
+++ b/src/arch/arm/isa_traits.hh
@@ -48,7 +48,7 @@
 #include "arch/arm/types.hh"
 #include "base/types.hh"
 
-namespace LittleEndianGuest {};
+namespace LittleEndianGuest {}
 
 #define TARGET_ARM
 
@@ -123,7 +123,7 @@
         INT_FIQ,
         NumInterruptTypes
     };
-};
+} // namespace ArmISA
 
 using namespace ArmISA;