Clarify which type "Label" refers to (generic vs X86)

src/IceAssemblerX86Base.h

Index: src/IceAssemblerX86Base.h
diff --git a/src/IceAssemblerX86Base.h b/src/IceAssemblerX86Base.h
index 917bd7bc1875ea9d7026284ca9098137338376f0..ccbfeb80050265b19637d44e81006ece56d035df 100644
--- a/src/IceAssemblerX86Base.h
+++ b/src/IceAssemblerX86Base.h
@@ -150,8 +150,9 @@ public:
       nop(Padding);
   }
 
-  Label *getOrCreateCfgNodeLabel(SizeT NodeNumber) override;
+  Ice::Label *getCfgNodeLabel(SizeT NodeNumber) override;
   void bindCfgNodeLabel(SizeT NodeNumber) override;
+  Label *getOrCreateCfgNodeLabel(SizeT Number);
   Label *getOrCreateLocalLabel(SizeT Number);
   void bindLocalLabel(SizeT Number);