Enable v4l2 probe on Linux/ARM
Enable v4l2 probe on Linux/ARM

Most of those have V4L2 drivers these days enabling it make sure that it
this code is enabled in major distribution, hence that HW accelerated
decoder/encoder can be used on platforms that support it. The probes are
slightly increasing the first init of gstreamer library, though the
result is cached in the registry for later use.

pexip/gst-plugins-good,hizukiayaka/gst-plugins-good,GrokImageCompression/gst-plugins-good,hizukiayaka/gst-plugins-good,StreamUtils/gst-plugins-good,hizukiayaka/gst-plugins-good,stfl/gst-plugins-good,GrokImageCompression/gst-plugins-good,GrokImageCompression/gst-plugins-good,GrokImageCompression/gst-plugins-good,pexip/gst-plugins-good,GStreamer/gst-plugins-good,GStreamer/gst-plugins-good,pexip/gst-plugins-good,GStreamer/gst-plugins-good,StreamUtils/gst-plugins-good,stfl/gst-plugins-good,stfl/gst-plugins-good,pexip/gst-plugins-good,pexip/gst-plugins-good,GStreamer/gst-plugins-good,stfl/gst-plugins-good,hizukiayaka/gst-plugins-good,StreamUtils/gst-plugins-good,StreamUtils/gst-plugins-good