[media] media drivers: annotate fall-through

Avoid warnings like those:

drivers/media/pci/ddbridge/ddbridge-core.c: In function 'dvb_input_detach':
drivers/media/pci/ddbridge/ddbridge-core.c:787:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (input->fe) {
      ^
drivers/media/pci/ddbridge/ddbridge-core.c:792:2: note: here
  case 4:
  ^~~~
...

On several cases, it is just that gcc 7.1 is not capable of
understanding the comment, but on other places, we need an
annotation.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/drivers/media/platform/sh_vou.c b/drivers/media/platform/sh_vou.c
index 992d61a..871da2a 100644
--- a/drivers/media/platform/sh_vou.c
+++ b/drivers/media/platform/sh_vou.c
@@ -229,6 +229,7 @@ static void sh_vou_stream_config(struct sh_vou_device *vou_dev)
 		break;
 	case V4L2_PIX_FMT_RGB565:
 		dataswap ^= 1;
+		/* fall through */
 	case V4L2_PIX_FMT_RGB565X:
 		row_coeff = 2;
 		break;
@@ -815,6 +816,7 @@ static u32 sh_vou_ntsc_mode(enum sh_vou_bus_fmt bus_fmt)
 	default:
 		pr_warn("%s(): Invalid bus-format code %d, using default 8-bit\n",
 			__func__, bus_fmt);
+		/* fall through */
 	case SH_VOU_BUS_8BIT:
 		return 1;
 	case SH_VOU_BUS_16BIT: