boards: circuitdojo_feather_nrf9160: disconnect SDO/SDA0 of LIS2DH12TR

LIS2DH12TR has an internal pull-up connected to SDA0 pin, while this pin
is connected directly to GND on PCB. This results in constant power
consumption, which can be prevented by disconnecting internal SDA0
pull-up. Do so by adding 'disconnect-sdo-sa0-pull-up' DT property, so
that accelerometer driver will send a proper command during boot.

Signed-off-by: Marcin Niestroj <m.niestroj@emb.dev>