sched, powerpc: Fix sched.h split-up build failure

sched, powerpc: Fix sched.h split-up build failure

Fix PowerPC/Cell build fallout from:

  8bd75c77b7c6 sched/rt: Move rt specific bits into new header file

Reported-by: Michael Ellerman <[email protected]>
Cc: Clark Williams <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>