emulators/yuzu: unbreak on FreeBSD < 12.2 after r548271

https://github.com/llvm/llvm-project/commit/86af6f5088b1

src/core/hle/service/sockets/bsd.cpp:450:55: error: no matching member function for call to 'emplace'

FileDescriptor& descriptor = file_descriptors[fd].emplace();
                             ~~~~~~~~~~~~~~~~~~~~~^~~~~~~

src/core/hle/service/sockets/bsd.cpp:545:63: error: no matching member function for call to 'emplace'

FileDescriptor& new_descriptor = file_descriptors[new_fd].emplace();
                                 ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~

/usr/include/c++/v1/optional:820:5: note: candidate template ignored: requirement 'is_constructible_v<Service::Sockets::BSD::FileDescriptor>' was not satisfied [with _Args = <>]

emplace(_Args&&... __args)
^

/usr/include/c++/v1/optional:835:5: note: candidate function template not viable: requires at least argument '__il', but no arguments were provided

emplace(initializer_list<_Up> __il, _Args&&... __args)
^