V4L/DVB (4229): Cx88-blackbird: implement VIDIOC_LOG_STATUS

implemented VIDIOC_LOG_STATUS in the cx88-blackbird driver
to show the status of i2c clients and the cx23416 mpeg encoder.

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>