iio: srf08: add support for srf02 in i2c mode

srf02 added with support for i2c interface

Attributes for setting max range or sensitivity are omitted for the case of
srf02 type sensor, because they are not supported by the hardware.

Signed-off-by: Andreas Klinger <ak@it-klinger.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>