Make RegARM32 a namespace rather than a class.

src/IceTargetLoweringARM32.h

Index: src/IceTargetLoweringARM32.h
diff --git a/src/IceTargetLoweringARM32.h b/src/IceTargetLoweringARM32.h
index 2f342e021af23773fd4aff2cda930053c0982cad..0d7d9cea408005416e8d2c9309e67aa9c55fee3b 100644
--- a/src/IceTargetLoweringARM32.h
+++ b/src/IceTargetLoweringARM32.h
@@ -1012,7 +1012,7 @@ protected:
   bool PrologEmitsFixedAllocas = false;
   uint32_t MaxOutArgsSizeBytes = 0;
   // TODO(jpp): std::array instead of array.
-  static llvm::SmallBitVector TypeToRegisterSet[RCARM32_NUM];
+  static llvm::SmallBitVector TypeToRegisterSet[RegARM32::RCARM32_NUM];
   static llvm::SmallBitVector RegisterAliases[RegARM32::Reg_NUM];
   static llvm::SmallBitVector ScratchRegs;
   llvm::SmallBitVector RegsUsed;