overlay: add r970-specific eri overlays

Change-Id: I6705b9f280ea9c8099b72ad7addb000fc1e4db2f
Merge "overlay: add r970-specific eri overlays" into cm-11.0
Merge branch 'cm-11.0' of github.com:CyanogenMod/android_device_samsung_qcom-common into cm-11.0