[media] exynos4-is: Ensure proper media pipeline state on device close

Make sure media_entity_pipeline_stop() is called on video device
close in cases where there was VIDIOC_STREAMON ioctl and no
VIDIOC_STREAMOFF. This patch fixes media entities stream_count
state which could prevent links from being disconnected, due to
non-zero stream_count.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>