i2c-i801: Don't depend on other kernel driver config options

Don't let other driver config options influence us, as it makes the
code more complex and fragile for a small benefit. There's nothing
wrong with instantiating I2C devices even if they don't have a driver.
And we're talking about 835 extra bytes in the binary on x86-64,
that's hardly worth arguing about.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: David Woodhouse <david.woodhouse@intel.com>
Cc: Hans de Goede <hdegoede@redhat.com>