video/via: drop deprecated (and unused) i2c_adapter.id

This patch removes an assignment to the deprecated i2c_adapter.id
field. Since the field isn't used anywhere else in the driver it is
save to remove it.

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>