modules: Move ProfileKinds to an anonymous namespace

Fix a build failure with `LLVM_ENABLE_MODULES` due to
`ProfileData::instr` conflicting with a function `instr()` in
`<curses.h>`.

llvm-svn: 239793
diff --git a/llvm/tools/llvm-profdata/llvm-profdata.cpp b/llvm/tools/llvm-profdata/llvm-profdata.cpp
index 1bfdb18..6fb48d8 100644
--- a/llvm/tools/llvm-profdata/llvm-profdata.cpp
+++ b/llvm/tools/llvm-profdata/llvm-profdata.cpp
@@ -37,7 +37,9 @@
   ::exit(1);
 }
 
+namespace {
 enum ProfileKinds { instr, sample };
+}
 
 static void mergeInstrProfile(const cl::list<std::string> &Inputs,
                               StringRef OutputFilename) {