s4-common: SystemUI: Use hardware layer for recents

Change-Id: Ic032c95adf4d3d1a9496862151868aef61524688
s4-common: Expand TARGET_RECOVERY_DEVICE_DIRS

+= doesn't expand immediately, so define this one explicitly.
Otherwise, build picks up "build/core" as the definition.

Change-Id: I6020a043b75c924f6af6a3bfdc0a1e25f1f4f982
Merge branch 'cm' into HEAD