[media] constify of_device_id array

of_device_id is always used as const.
(See driver.of_match_table and open firmware functions)

[mchehab@osg.samsung.com: fix a merge conflict at adv7604.c]
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Acked-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>