Move qemu_spice_set_passwd() and qemu_spice_set_pw_expire() functions to
QemuSpiceOps.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 20201019075224.14803-7-kraxel@redhat.com