V4L/DVB: cx23885: Add a VIDIOC_LOG_STATUS ioctl function for analog video devices

Add a simple log_status function for raw analog video capture device nodes,
to provide insight into the state of the CX2388[578] A/V decoder core.

Signed-off-by: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>