Add missing header

Author: wangpc-pp

llvm/lib/TargetParser/Host.cpp

@@ -18,6 +18,7 @@
 #include "llvm/Config/llvm-config.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/TargetParser/RISCVTargetParser.h"
 #include "llvm/TargetParser/Triple.h"
 #include "llvm/TargetParser/X86TargetParser.h"
 #include <string.h>