i2c/writing-clients: Fix foo_driver.id_table

commit 3116c860 upstream.

The i2c_device_id structure variable's name is not used in the
i2c_driver structure.

Signed-off-by: Vikram Narayanan <vikram186@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>