Add POWER6 and POWER7 CPU types to the PPC backend.

No functional change; these will be used by upcoming scheduler enhancements.

llvm-svn: 158313
diff --git a/llvm/lib/Target/PowerPC/PPCSubtarget.h b/llvm/lib/Target/PowerPC/PPCSubtarget.h
index a275029..744a630 100644
--- a/llvm/lib/Target/PowerPC/PPCSubtarget.h
+++ b/llvm/lib/Target/PowerPC/PPCSubtarget.h
@@ -41,6 +41,8 @@
     DIR_750, 
     DIR_970, 
     DIR_A2,
+    DIR_PWR6,
+    DIR_PWR7,
     DIR_64  
   };
 }