Revert "overall_stats: forward port to kernel 3.4+"

This reverts commit 8c51c49f7b9be8dab6d298358db7383271c73dcc.
Revert "overall_stats: make dual/quad core stats configurable via meunconfig"

This reverts commit abe8ce02e240a880c1447f1c072d06ea394ad6a2.
Revert "overall_stats: add overall stats for all available cores"

This reverts commit 74d59fc50e3a6e079ee9c0a3a115ea5cc3720696.