[media] soc_camera: annotate a switch fall through

Clearly, hsync and vsinc bool vars are part of the return
logic on the second case of the switch. Annotate that, in
order to shut up gcc warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/soc_camera/soc_mediabus.c

@@ -494,6 +494,7 @@ unsigned int soc_mbus_config_compatible(const struct v4l2_mbus_config *cfg,
 					V4L2_MBUS_HSYNC_ACTIVE_LOW);
 		vsync = common_flags & (V4L2_MBUS_VSYNC_ACTIVE_HIGH |
 					V4L2_MBUS_VSYNC_ACTIVE_LOW);
+		/* fall through */
 	case V4L2_MBUS_BT656:
 		pclk = common_flags & (V4L2_MBUS_PCLK_SAMPLE_RISING |
 				       V4L2_MBUS_PCLK_SAMPLE_FALLING);