ARM: shmobile: kzm9g: enable three-axis digital accelerometer ADXL345

This patch enables three-axis digital accelerometer ADXL345.
Test:
  sudo cat /dev/input/event2
then tip up the board. You get something from /dev/input/event2.

Signed-off-by: Tetsuyuki Kobayashi <koba@kmckk.co.jp>
Signed-off-by: Simon Horman <horms@verge.net.au>