[media] s2255drv: Add MODULE_FIRMWARE statement

Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Dean Anderson <linux-dev@sensoray.com>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: linux-media@vger.kernel.org
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>