Revert "sched: Fix select_idle_sibling() regression in selecting an idle SMT sibling"

This reverts commit a388981be5df7d93e9ba73fd5daefe2d64b178ee.
Revert "sched: Fix buglet in return_cfs_rq_runtime()"

This reverts commit 5fbd85c7a263c1d678c7901f4f38b113f1f2da4e.
Revert "sched: Avoid SMT siblings in select_idle_sibling() if possible"

This reverts commit ed508b1cd6a6b18944a400aaa1b02e20965231e5.
Revert "mach-tegra: cpu-tegra3.c: default to dual core"

This reverts commit f75a7ffbfa1fbf1336753cf65cbff03f748d0866.