media: cx25840: make array stds static const, reduces object code size

Don't populate the array syds on the stack, instead make it static const.
Makes the object code smaller by over 280 bytes:

Before:
   text	   data	    bss	    dec	    hex	filename
  81451	  12784	    704	  94939	  172db	cx25840-core.o

   text	   data	    bss	    dec	    hex	filename
  81070	  12880	    704	  94654	  171be	cx25840-core.o
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NHans Verkuil <hansverk@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/i2c/cx25840/cx25840-core.c

@@ -1745,7 +1745,7 @@ static int cx25840_g_std(struct v4l2_subdev *sd, v4l2_std_id *std)
 {
 	struct i2c_client *client = v4l2_get_subdevdata(sd);
 
-	v4l2_std_id stds[] = {
+	static const v4l2_std_id stds[] = {
 		/* 0000 */ V4L2_STD_UNKNOWN,
 
 		/* 0001 */ V4L2_STD_NTSC_M,