media: vicodec: constify v4l2_ctrl_ops structure

The v4l2_ctrl_ops structure is only stored in the ops field of a
v4l2_ctrl_config structure, and this field is const, or passed as the
second argument of v4l2_ctrl_new_std, and the corresponding parameter
is declared as const.  Accordingly, the structure can also be const.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>