[media] vivid: Don't declare .vidioc_overlay twice

Removes the following warnings:

drivers/media/platform/vivid/vivid-core.c:581:2: warning: initialized field overwritten [-Woverride-init]
  .vidioc_overlay   = vidioc_overlay,
  ^
drivers/media/platform/vivid/vivid-core.c:581:2: warning: (near initialization for 'vivid_ioctl_ops.vidioc_overlay') [-Woverride-init]
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/platform/vivid/vivid-core.c

@@ -578,7 +578,6 @@ static const struct v4l2_ioctl_ops vivid_ioctl_ops = {
 	.vidioc_g_fmt_vid_out_overlay	= vidioc_g_fmt_vid_out_overlay,
 	.vidioc_try_fmt_vid_out_overlay	= vidioc_try_fmt_vid_out_overlay,
 	.vidioc_s_fmt_vid_out_overlay	= vidioc_s_fmt_vid_out_overlay,
-	.vidioc_overlay			= vidioc_overlay,
 	.vidioc_g_fbuf			= vidioc_g_fbuf,
 	.vidioc_s_fbuf			= vidioc_s_fbuf,