keylayout: add AK8789 configuration file

- add AK8789 config file
- remove unused config files

Change-Id: I3e966bea402ea37010db0d20bc7d39c5f4677bf5
Merge branch 'cm-11.0' of https://github.com/htc-msm8974/android_device_htc_msm8974-common into cm-11.0