[LLD][WASM] Handle WASM_SYMBOL_TYPE_SECTION in toString().

Fixes build. If this is not the desired solution, please revert.
WasmSymbolType was changed in rL330982 / D44184

llvm-svn: 330984

lld/wasm/Symbols.cpp

@@ -231,6 +231,8 @@ std::string lld::toString(WasmSymbolType Type) {
     return "Data";
   case llvm::wasm::WASM_SYMBOL_TYPE_GLOBAL:
     return "Global";
+  case llvm::wasm::WASM_SYMBOL_TYPE_SECTION:
+    return "Section";
   }
   llvm_unreachable("invalid symbol type");
 }