iio: mma8452: driver improvements for v4.6

[Martin Kepplinger]

This includes my pending changes for the mma8452 driver for v4.6.
It hopefully makes the auto builder happy and simplifies the thing
on the mailing lists.

[PATCH v6 1/3] iio: mma8452: add freefall detection for Freescale's

[PATCH 2/3] iio: mma8452: whitespace cleanup

[PATCH 3/3] iio: mma8452: add support for MMA8451Q
Strictly this is v2, after Peter's and Jonathan's review.