AMDGPU: Fix getArchTypePrefix

llvm-svn: 258525
diff --git a/llvm/lib/Support/Triple.cpp b/llvm/lib/Support/Triple.cpp
index e8591ff..5099cd5 100644
--- a/llvm/lib/Support/Triple.cpp
+++ b/llvm/lib/Support/Triple.cpp
@@ -94,8 +94,8 @@
 
   case hexagon:     return "hexagon";
 
-  case amdgcn:
-  case r600:        return "amdgpu";
+  case amdgcn:      return "amdgcn";
+  case r600:        return "r600";
 
   case bpfel:
   case bpfeb:       return "bpf";