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

llvm-svn: 304872
diff --git a/clang/lib/Sema/SemaCodeComplete.cpp b/clang/lib/Sema/SemaCodeComplete.cpp
index 224d9e9..b9349dc 100644
--- a/clang/lib/Sema/SemaCodeComplete.cpp
+++ b/clang/lib/Sema/SemaCodeComplete.cpp
@@ -1860,6 +1860,7 @@
 
     AddStaticAssertResult(Builder, Results, SemaRef.getLangOpts());
   }
+  LLVM_FALLTHROUGH;
 
   // Fall through (for statement expressions).
   case Sema::PCC_ForInit: