Fix missing register class.

src/IceTargetLoweringARM32.cpp

Index: src/IceTargetLoweringARM32.cpp
diff --git a/src/IceTargetLoweringARM32.cpp b/src/IceTargetLoweringARM32.cpp
index 2da554286a9abc40e3a043775031eba0ca4208c7..e97c8cd926266b85662aa8458f5cf84ea8e3b298 100644
--- a/src/IceTargetLoweringARM32.cpp
+++ b/src/IceTargetLoweringARM32.cpp
@@ -278,7 +278,9 @@ IceString getRegClassName(RegClass C) {
   default:
     assert(C < RC_Target);
     return regClassString(C);
-    // Add handling of new register classes below.
+  // Add handling of new register classes below.
+  case RegARM32::RCARM32_QtoS:
+    return "QtoS";
   }
 }