hwmon: (pmbus/lm25066) Let enum chips start with index 0

hwmon: (pmbus/lm25066) Let enum chips start with index 0

Commit ac0c26bae662 ("hwmon: (lm25066) Use i2c_get_match_data()") changed
enum chips to start with 1 instead of 0, under the assumption that
the data pointer in of_device_id must not start with 0 (NULL) if
i2c_get_match_data() is used. However, that is perfectly fine as long as
there is also an i2c_device_id array with the same data which is used
as fallback in that case.

Let enum chips start with 0 to avoid confusion against other drivers
where the enum starts with 0 and i2c_get_match_data() is used as well.

Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>