sched: Hide runqueues from direct reference at source code level for __raw_get_cpu_var()

Hide __raw_get_cpu_var() as well - thus all the direct
references to runqueues will abstracted out.

Signed-off-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
LKML-Reference: <20090629.144457.886429910353660979.mitake@dcl.info.waseda.ac.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>