win32u: Move NtUserAddClipboardFormatListener and NtUserRemoveClipboardFormatListener implementations from user32.
Signed-off-by: Jacek Caban <jacek@codeweavers.com>
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>