Fix typo. This method isn't used anywhere.

llvm-svn: 178453

clang/include/clang/Basic/Diagnostic.h

@@ -436,7 +436,7 @@ public:
   ///
   /// If this and IgnoreAllWarnings are both set, then that one wins.
   void setEnableAllWarnings(bool Val) { EnableAllWarnings = Val; }
-  bool getEnableAllWarnngs() const { return EnableAllWarnings; }
+  bool getEnableAllWarnings() const { return EnableAllWarnings; }
 
   /// \brief When set to true, any warnings reported are issued as errors.
   void setWarningsAsErrors(bool Val) { WarningsAsErrors = Val; }