Added LLVM_FALLTHROUGH to address warning: this statement may fall through. NFC.

llvm-svn: 304641
diff --git a/clang/lib/Analysis/ScanfFormatString.cpp b/clang/lib/Analysis/ScanfFormatString.cpp
index 3b93f1a..5342259 100644
--- a/clang/lib/Analysis/ScanfFormatString.cpp
+++ b/clang/lib/Analysis/ScanfFormatString.cpp
@@ -341,6 +341,7 @@
         case LengthModifier::AsShort:
           if (Ctx.getTargetInfo().getTriple().isOSMSVCRT())
             return ArgType::PtrTo(ArgType::AnyCharTy);
+          LLVM_FALLTHROUGH;
         default:
           return ArgType::Invalid();
       }
@@ -357,6 +358,7 @@
         case LengthModifier::AsShort:
           if (Ctx.getTargetInfo().getTriple().isOSMSVCRT())
             return ArgType::PtrTo(ArgType::AnyCharTy);
+          LLVM_FALLTHROUGH;
         default:
           return ArgType::Invalid();
       }