Input: mms114 - switch to using managed resources

devm_* APIs are device managed and make the exit and clean up code
simpler.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Laxman <Dewangan&lt;ldewangan@nvidia.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>