i2c-voodoo3: Deprecate in favor of tdfxfb

Support for I2C/DDC was recently added to the tdfxfb driver, which
means that the i2c-voodoo3 driver can be deprecated.

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