[Xtensa] Add Xtensa builtins into last builtin ID calculation

Author: gerekon

clang/include/clang/Basic/TargetBuiltins.h

@@ -383,7 +383,7 @@ namespace clang {
        PPC::LastTSBuiltin, NVPTX::LastTSBuiltin, AMDGPU::LastTSBuiltin,
        X86::LastTSBuiltin, VE::LastTSBuiltin, RISCV::LastTSBuiltin,
        Hexagon::LastTSBuiltin, Mips::LastTSBuiltin, XCore::LastTSBuiltin,
-       SystemZ::LastTSBuiltin, WebAssembly::LastTSBuiltin});
+       SystemZ::LastTSBuiltin, WebAssembly::LastTSBuiltin, Xtensa::LastTSBuiltin});
 
 } // end namespace clang.