[clang-tidy][Fuchsia]: don't forget to actually link to Google Module.

Fixes build for me:

[1/7] Linking CXX shared library lib/libclangTidyFuchsiaModule.so.7svn
FAILED: lib/libclangTidyFuchsiaModule.so.7svn
<...>
/usr/local/bin/ld.lld: error: undefined symbol: clang::tidy::google::build::UnnamedNamespaceInHeaderCheck::UnnamedNamespaceInHeaderCheck(llvm::StringRef, clang::tidy::ClangTidyContext*)
>>> referenced by FuchsiaTidyModule.cpp
>>>               tools/clang/tools/extra/clang-tidy/fuchsia/CMakeFiles/clangTidyFuchsiaModule.dir/FuchsiaTidyModule.cpp.o:(std::_Function_handler<clang::tidy::ClangTidyCheck* (llvm::StringRef, clang::tidy::ClangTidyContext*), void clang::tidy::ClangTidyCheckFactories::registerCheck<clang::tidy::google::build::UnnamedNamespaceInHeaderCheck>(llvm::StringRef)::'lambda'(llvm::StringRef, clang::tidy::ClangTidyContext*)>::_M_invoke(std::_Any_data const&, llvm::StringRef&&, clang::tidy::ClangTidyContext*&&))

Refs. D45447, rCTE329720

llvm-svn: 329749