platform/mulle/lis3dh: Add interface for choosing axes.

Signed-off-by: Joakim Gebart <joakim.gebart@eistec.se>
examples/lis3dh-fifo: Clean up

Signed-off-by: Joakim Gebart <joakim.gebart@eistec.se>
examples/lis3dh-poll: Set axes and disable FIFO.

Signed-off-by: Joakim Gebart <joakim.gebart@eistec.se>