i2c: Do not probe for TV chips on Voodoo3 adapters

There's no point in giving the I2C bus of Voodoo3 adapters a class
value, there's no video chip driver checking for it anymore. If
support is ever needed, the video device should be instantiated
explicitly rather than probed.

To the best of my knowledge the only video chip that can be found on
these boards is a BT869 video encoder, for which no support exists
currently.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Krzysztof Helt <krzysztof.h1@wp.pl>