media: ov5645: constify v4l2_ctrl_ops structure

The v4l2_ctrl_ops structure is only passed as the second argument to
functions such as v4l2_ctrl_new_std for which the corresponding
parameter is const, so make the v4l2_ctrl_ops structure const as well.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>