trace/sched: Add NR_CPUS check for load balancer trace points

Compilation fails for systems with NR_CPUS > 32 due to load balancer
trace points. Instead of failing compilation, add NR_CPUS checks for
these trace points which should be good enough to make sure trace points
won't even be available for such systems.

Change-Id: I0f722b32dbec999d3de31efcd135db25905604aa
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>