Add namespace comments for doxygen


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@6581 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86CodeEmitter.cpp b/lib/Target/X86/X86CodeEmitter.cpp
index 3b7fb4c..f41300d 100644
--- a/lib/Target/X86/X86CodeEmitter.cpp
+++ b/lib/Target/X86/X86CodeEmitter.cpp
@@ -264,8 +264,9 @@
 
 
 
-
-namespace N86 {  // Native X86 Register numbers...
+/// N86 namespace - Native X86 Register numbers... used by X86 backend.
+///
+namespace N86 {
   enum {
     EAX = 0, ECX = 1, EDX = 2, EBX = 3, ESP = 4, EBP = 5, ESI = 6, EDI = 7
   };