video_input: fix crash when touchpad v4l has video capabilities

Change-Id: Ie24e29fc97f1f83cc0148c1c75788cef8f1008df

src/media/video/v4l2/video_device_impl.cpp

@@ -449,6 +449,9 @@ VideoDeviceImpl::VideoDeviceImpl(const string& path)
     if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE))
         throw std::runtime_error("not a capture device");
 
+    if (cap.capabilities & V4L2_CAP_TOUCH)
+        throw std::runtime_error("touch device, ignoring it");
+
     name = string(reinterpret_cast<const char*>(cap.card));
 
     v4l2_input input;