video-stream: Don't stop a stream associated with gl_draw (v2)

We do not want to stop a stream associated with gl_draw as a result
of timeout because we may not get another opportunity to create a
new stream if the current one gets stopped. However, when the
stream does get stopped for other reasons, we need to clear the
gl_draw_stream pointer associated with the relevant DC.

v2: (suggestions from Frediano)
- Don't stop the stream regardless of whether gl_draw is ongoing
  or not

Cc: Frediano Ziglio <freddy77@gmail.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: Dongwon Kim <dongwon.kim@intel.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>