[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>

drivers/media/usb/dvb-usb/dib0700_devices.c

@@ -1659,6 +1659,7 @@ static int dib8096_set_param_override(struct dvb_frontend *fe)
 	switch (band) {
 	default:
 			deb_info("Warning : Rf frequency  (%iHz) is not in the supported range, using VHF switch ", fe->dtv_property_cache.frequency);
+			/* fall through */
 	case BAND_VHF:
 			state->dib8000_ops.set_gpio(fe, 3, 0, 1);
 			break;

drivers/media/usb/dvb-usb/dw2102.c

@@ -1840,11 +1840,12 @@ static int dw2102_load_firmware(struct usb_device *dev,
 		switch (le16_to_cpu(dev->descriptor.idProduct)) {
 		case USB_PID_TEVII_S650:
 			dw2104_properties.rc.core.rc_codes = RC_MAP_TEVII_NEC;
+			/* fall through */
 		case USB_PID_DW2104:
 			reset = 1;
 			dw210x_op_rw(dev, 0xc4, 0x0000, 0, &reset, 1,
 					DW210X_WRITE_MSG);
-			/* break omitted intentionally */
+			/* fall through */
 		case USB_PID_DW3101:
 			reset = 0;
 			dw210x_op_rw(dev, 0xbf, 0x0040, 0, &reset, 0,
@@ -1877,6 +1878,7 @@ static int dw2102_load_firmware(struct usb_device *dev,
 					break;
 				}
 			}
+			/* fall through */
 		case 0x2101:
 			dw210x_op_rw(dev, 0xbc, 0x0030, 0, &reset16[0], 2,
 					DW210X_READ_MSG);