V4L/DVB (9883): gspca - ov534: Show sensor ID.

The original version of sccb_read_reg() is from Jim Paris.

NOTE: as it is now reading sensor ID won't work for sensors on different
i2c slave address.

Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>