Add a null implementation library for QemuFwCfgLib, in order to support building PciHostBridgeLib for bhyve. Signed-off-by: Rebecca Cran <rebecca@bsdio.com> Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Laszlo Ersek <lersek@redhat.com> Cc: Ard Biesheuvel <ard.biesheuvel@arm.com> Cc: Philippe Mathieu-Daudé <philmd@redhat.com> Message-Id: <20200503230910.26783-1-rebecca@bsdio.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com>