Revert "sched: Introduce temporary FAIR_GROUP_SCHED dependency for load-tracking"

Revert "sched: Introduce temporary FAIR_GROUP_SCHED dependency for load-tracking"

Remove CONFIG_FAIR_GROUP_SCHED that covers the runnable info, then
we can use runnable load variables.

Also remove 2 CONFIG_FAIR_GROUP_SCHED setting which is not in reverted
patch(introduced in 74c332c), but also need to revert.

Signed-off-by: Alex Shi <alex.shi@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51CA76A3.3050207@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>