Change the name to be in style.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223255 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/MC/MCSubtargetInfo.h

@@ -138,7 +138,7 @@ public:
   void initInstrItins(InstrItineraryData &InstrItins) const;
 
   /// Check whether the CPU string is valid.
-  bool CPUStringIsValid(StringRef CPU) {
+  bool isCPUStringValid(StringRef CPU) {
     auto Found = std::find_if(ProcDesc.begin(), ProcDesc.end(),
                               [=](const SubtargetFeatureKV &KV) {
                                 return CPU == KV.Key;