s4-common: utilize recovery_root_private

Prebuilt modules can be placed in the correct directory structure under
recovery/root and the build system will automatically copy them to the
recovery ramdisk.

Move offmode charging images to devices since they are resolution
dependent.

Change-Id: I36cb2dc104a250c6f63f009b8b78aa1078808927
Merge remote-tracking branch 'cm/cm-11.0' into HEAD