media: platform: make video_device const

Make these const as they are only used during a copy operation.
Done using Coccinelle:

@match disable optional_qualifier@
identifier s;
@@
static struct video_device s = {...};

@ref@
position p;
identifier match.s;
@@
s@p

@good1@
identifier match.s;
expression list[3] es;
position ref.p;
@@
cx88_vdev_init(es,&s@p,...)

@good2@
position ref.p;
identifier match.s,f,c;
expression e;
@@
(
e = s@p
|
e = s@p.f
|
c(...,s@p.f,...)
|
c(...,s@p,...)
)

@bad depends on  !good1 && !good2@
position ref.p;
identifier match.s;
@@
s@p

@depends on forall !bad disable optional_qualifier@
identifier match.s;
@@
static
+ const
struct video_device s;

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/vim2m.c

@@ -974,7 +974,7 @@ static const struct v4l2_file_operations vim2m_fops = {
 	.mmap		= v4l2_m2m_fop_mmap,
 };
 
-static struct video_device vim2m_videodev = {
+static const struct video_device vim2m_videodev = {
 	.name		= MEM2MEM_NAME,
 	.vfl_dir	= VFL_DIR_M2M,
 	.fops		= &vim2m_fops,