The accelerometers/gyro on the Sixaxis are reported in the wrong
endianness (ie. not compatible with HID), so this patch intercepts
the report and swaps the appropriate bytes over.

Accelerometers are scaled with a nominal value of +/-4000 = 1G,
maximum value would be around +/-32768 = 8G.

Gyro on my device always reports -32768, might need some calibration
set within the controller.

Fix extracted from previous patch submission:
https://patchwork.kernel.org/patch/95212/Signed-off-by: Marcin Tolysz <tolysz@gmail.com>
Signed-off-by: Simon Wood <simon@mungewell.org>
Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>