boards: Set devicetree alias for ST LIS3DH nodes

Set accel0 alias for all boards with the LIS3DH accelerometer
to use by the accel_polling sample.

Add "st,lis2dh" compatibility to resolve dependency
to 96b_wistrio and rak5010_nrf52840.

Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@fujitsu.com>